1. No category

Recurrent First Trimester Pregnancy Loss
Contents
Foreword
ix
William F. Rayburn
Preface: Recurrent Pregnancy Loss
xi
William H. Kutteh
Classic and Cutting-Edge Strategies for the Management of Early Pregnancy Loss
1
Paul R. Brezina and William H. Kutteh
There are few conditions in medicine associated with more heartache to
patients than recurrent pregnancy loss (RPL). The management of early
RPL is a formidable clinical challenge for physicians. Great strides have
been made in characterizing the incidence and diversity of this heterogeneous disorder and a definite cause of pregnancy loss can be established
in more than half of couples after a thorough evaluation. In this review, current data are evaluated and a clear roadmap is provided for the evaluation
and treatment of RPL.
Research Methodology in Recurrent Pregnancy Loss
19
Ole B. Christiansen
The aim of this article is to highlight pitfalls in research methodology that
may explain why studies in recurrent pregnancy loss (RPL) often provide
very divergent results. It is hoped that insight into this issue will help
clinicians decide which published studies are the most valid. It may help
researchers to eliminate methodological flaws in future studies, which
will hopefully lead to some kind of agreement about the usefulness of
diagnostic tests and treatments in RPL.
The Evolving Role of Genetics in Reproductive Medicine
41
Paul R. Brezina and William G. Kearns
As medicine has evolved over the last century, medical genetics has grown
from nonexistence to one of the most visible aspects of how we understand and treat disease. This increased role of genetics within medicine
will only increase in the coming years, and its role in reproductive medicine
will be significant. Genetics has emerged as a primary focus of research
with translational applications within reproductive medicine. The aim of
this article is to outline the applications of genetics currently available
and how these technologies can provide a positive impact on patient care.
Uterine Factors
Carolyn R. Jaslow
Uterine anomalies are one of the most common parental causes of recurrent pregnancy loss, occurring in about 19% of patients. Congenital
57
vi
Contents
uterine anomalies are most likely caused by HOX gene mutations,
although the mechanism is probably polygenic. There are no known
environmental causes other than estrogenic endocrine disruptors such
as diethylstilbestrol. Acquired uterine anomalies may result from uterine
trauma (adhesions) or benign growths of the myometrium (fibroids) or
endometrium (polyps). Although randomized controlled trials are lacking,
surgical treatment is recommended for repair of uterine septa, and for
removal of severe adhesions and submucosal fibroids, especially if no
other causes are identified.
Mid-Trimester Pregnancy Loss
87
Kelly M. McNamee, Feroza Dawood, and Roy G. Farquharson
Mid-trimester pregnancy loss (MTL) occurs between 12 and 24 weeks’
gestation. The true incidence of this pregnancy complication is unknown,
because research into MTL in isolation is scarce, although the estimated
incidence has been noted to be 2% to 3% of pregnancies. A comprehensive preconceptual screening protocol is recommended, because the
cause for an MTL may be present in isolation or combined (dual pathology), and is often heterogeneous. Patients with a history of MTL are
at an increased risk of future miscarriage and preterm delivery. This risk
is increased further depending on the number of associative factors
diagnosed.
Endocrine Basis for Recurrent Pregnancy Loss
103
Raymond W. Ke
Common endocrinopathies are a frequent contributor to spontaneous and
recurrent miscarriage. Although the diagnostic criteria for luteal phase
defect (LPD) is still controversial, treatment of patients with both recurrent
pregnancy loss and LPD using progestogen in early pregnancy seems
beneficial. For patients who are hypothyroid, thyroid hormone replacement therapy along with careful monitoring in the preconceptual and early
pregnancy period is associated with improved outcome. Women with
polycystic ovary syndrome (PCOS) have an increased risk of pregnancy
loss. Management of PCOS with normalization of weight or metformin
seems to reduce the risk of pregnancy loss.
Antiphospholipid Antibody Syndrome
William H. Kutteh and Candace D. Hinote
Antiphospholipid antibodies (aPLs) are acquired antibodies directed
against negatively charged phospholipids. Obstetric antiphospholipid
antibody syndrome (APS) is diagnosed in the presence of certain clinical
features in conjunction with positive laboratory findings. Obstetric APS is
one of the most commonly identified causes of recurrent pregnancy
loss. Thus, obstetric APS is distinguished from APS in other organ systems
where the most common manifestation is thrombosis. Several pathophysiologic mechanisms of action of aPLs have been described. This article
discusses the diagnostic and obstetric challenges of obstetric APS, proposed pathophysiologic mechanisms of APS during pregnancy, and the
management of women during and after pregnancy.
113
Contents
Inherited Thrombophilias and Adverse Pregnancy Outcomes: A Review of
Screening Patterns and Recommendations
133
William B. Davenport and William H. Kutteh
Historically, much controversy has existed regarding the association of
inherited thrombophilias with adverse pregnancy outcomes. The current
guidelines do not recommend screening unless a personal history of
venous thromboembolism is present, but the authors’ survey of physician
screening patterns has suggested that up to 40% of physicians may
screen contrary to the current guidelines. This article summarizes the
existing evidence for each inherited thrombophilia and reviews the current
guidelines.
Recurrent Miscarriage Clinics
145
M.M.J. Van den Berg, Rosa Vissenberg, and Mariëtte Goddijn
A recurrent miscarriage clinic offers specialist investigation and treatment of women with recurrent first- and second-trimester miscarriages.
Consultant-led clinics provide a dedicated and focused service to couples who have experienced at least two prior miscarriages. The best
treatment strategy for couples with recurrent miscarriage is to discuss
a treatment plan for a future pregnancy. Evidence-based up-to-date
guidelines are required to reduce ineffective management of recurrent
miscarriage couples, including overdiagnostics and underdiagnostics.
Scientific research is necessary to study the effectiveness of new interventions, to study patient preferences, and to evaluate health care and
costs or other outcomes.
Unexplained Recurrent Pregnancy Loss
157
Sotirios H. Saravelos and Lesley Regan
Women with unexplained recurrent pregnancy loss (RPL) represent a highly
heterogeneous group of patients. Past studies have investigated systemic
endocrine and immunologic mechanisms as potential causes for pregnancy loss in unexplained RPL, while exciting new work has focused on
spermatozoal, embryonic, and endometrial characteristics to explain the
regulation of implantation and subsequent pregnancy loss. In the clinical
and research context, stratification of women with unexplained RPL
according to whether they have a high probability of pathologic status
will help select women who are most appropriate for further investigation
and potential future treatment.
Index
167
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Classic and Cutting-Edge
S t r a t e g i e s f o r th e M a n a g e m e n t o f
Early Pregnancy L oss
Paul R. Brezina,
MD, MBA*,
William H. Kutteh,
MD, PhD, HCLD
KEYWORDS
Recurrent pregnancy loss RPL Miscarriage Spontaneous abortion Aneuploid
Antiphospholipid Lupus anticoagulant Heparin
KEY POINTS
There are few conditions in medicine associated with more heartache to patients than
recurrent pregnancy loss (RPL).
The management of early RPL is a formidable clinical challenge for physicians.
Great strides have been made in characterizing the incidence and diversity of this heterogeneous disorder, and a definite cause of pregnancy loss can be established in more than
half of couples after a thorough evaluation.
In this review, current data are evaluated and a clear roadmap is provided for the evaluation and treatment of RPL.
INTRODUCTION
Recurrent early pregnancy loss is a profound personal tragedy to couples seeking
parenthood and a formidable clinical challenge to their physician. When to evaluate
a couple and what constitutes a complete evaluation is, at the time of the writing of
this article, in a state of flux. The American College of Obstetricians and Gynecologists
(ACOG) has withdrawn its 2001 Practice Bulletin on early RPL and has not issued a
replacement for more than 1 year. The American Society for Reproductive Medicine
Disclosure: Contributors: P.R. Brezina primarily searched the literature. P.R. Brezina wrote the
first draft of the article; W.H. Kutteh edited the article and advised on the content of the article,
assisted in the literature search, and contributed to the writing of the article. P.R. Brezina is
guarantor.
Competing Interests: All authors have completed the Unified Competing Interest form and
declare: no support from any organization for the submitted work; no financial relationships
with any organizations that might have an interest in the submitted work in the previous 3
years; and no other relationships or activities that could appear to have influenced the submitted work.
Sources of Funding: None.
Fertility Associates of Memphis, 80 Humphreys Center, Suite 307, Memphis, TN 38120, USA
* Corresponding author.
E-mail address: pbrezina@fertilitymemphis.com
Obstet Gynecol Clin N Am 41 (2014) 1–18
http://dx.doi.org/10.1016/j.ogc.2013.10.011
obgyn.theclinics.com
0889-8545/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
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Brezina & Kutteh
(ASRM) has recently released a committee opinion after extensively evaluating available evidence over a 7-year period.1
Although spontaneous abortion occurs in approximately 15% of clinically diagnosed
pregnancies of reproductive-aged women, recurrent pregnancy loss (RPL) occurs in
about 1% to 2% of this same population.2 Great strides have been made in characterizing the incidence and diversity of this heterogeneous disorder, and a definite cause of
pregnancy loss can be established in more than half of couples after a thorough evaluation.3,4 A complete evaluation includes investigations into genetic, endocrinologic,
anatomic, immunologic, and iatrogenic causes. The occurrence of RPL may induce significant emotional distress, and, in some cases, intensive supportive care may be
necessary. Successful outcomes occur in more than two-thirds of all couples.4,5
DEFINITION OF PREGNANCY LOSS
The traditional definition of RPL included those couples with 3 or more spontaneous,
consecutive pregnancy losses. Ectopic and molar pregnancies are not included. The
ASRM has defined RPL as “a distinct disorder defined by 2 or more failed clinical pregnancies.”1 For purposes of determining if an evaluation for RPL is appropriate, pregnancy “is defined as a clinical pregnancy documented by ultrasonography or
histopathological examination.”1 Several studies have recently indicated that the
risk of recurrent miscarriage after 2 successive losses is similar to the risk of miscarriage in women after 3 successive losses; thus, it is reasonable to start an evaluation
after 2 or more consecutive spontaneous miscarriages to determine the cause of their
pregnancy loss, especially when the woman is older than 35 years of age, or when the
couple have had difficulty conceiving.6
Those couples with primary RPL have never had a previous viable infant, whereas
those with secondary recurrent loss have previously delivered a pregnancy beyond
20 weeks and then suffered subsequent losses. Tertiary recurrent loss refers to those
women who have multiple miscarriages interspersed with normal pregnancies.
RECURRENCE RISK
The main concerns of couples with recurrent miscarriage when they present to our
RPL center is to find the cause and to establish the risk of recurrence. In a first pregnancy, the overall risk of loss of a clinically recognized pregnancy loss is 15%.7,8 However, the true risk of early pregnancy loss is estimated to be around 50% because of
the high rate of losses that occur before the first missed menstrual period. Furthermore, as women age, this rate likely increases because of chromosomal errors introduced through meiotic nondisjunction errors during oocyte maturation. Studies that
evaluated the frequency of pregnancy loss,7,8 based on highly sensitive tests for quantitative human chorionic gonadotropin (hCG), indicated that the total clinical and preclinical losses in women aged 20 to 30 years is approximately 25%, whereas the loss
rate in women aged 40 years or more is at least double that figure. The ability to predict
the risk of recurrence is influenced by several factors, including maternal age, parental
and fetal karyotypes, the gestational age at which prior losses occurred, and the presence of various maternal laboratory findings.8–14
CAUSES, DIAGNOSIS, AND TREATMENT OF RPL
Introduction
Traditionally, the chief causes of RPL have been believed to be embryonic chromosomal abnormalities, maternal anatomic abnormalities such as a uterine septum, luteal
Management of Early Pregnancy Loss
phase defects, and antiphospholipid (aPL) antibodies. Other factors such as infection
and a hypercoaguable state have also been considered but to a lesser degree.
When to initiate an RPL workup has been a source of recent debate. Classically,
conducting a workup for RPL was recommended after 3 miscarriages. Recent data
do not necessarily support this traditional evaluation protocol.15,16 The evaluation of
healthy women after a single loss is usually not recommended, because this a common, sporadic event. However, the risk of another pregnancy loss after 2 miscarriages
is only slightly lower (24%–29%) than that of women with 3 or more spontaneous abortions (31%–33%).7 Therefore, evaluation and treatment can reasonably be started after 2 consecutive miscarriages.1,4 Furthermore, additional testing such as
chromosomal testing of the products of conception from a second miscarriage may
confer a cost-savings measure.15,16 Based on available data, we outline a new strategy for the workup of RPL (Figs. 1 and 2).
An evaluation of a patient with RPL should always include a complete history,
including documentation of previous pregnancies, any pathologic tests that were performed on previous miscarriages, any evidence of chronic or acute infections or diseases, any recent physical or emotional trauma, history of cramping or bleeding with a
previous miscarriage, any family history of pregnancy loss, and any previous gynecologic surgery or complicating factor. A summary of the diagnosis and management of
RPL includes an investigation of genetic, endocrinologic, anatomic, immunologic, and
iatrogenic causes (Table 1).
We outline a proposed algorithm for the evaluation and treatment of RPL (see
Fig. 1). Under this new schema, no diagnostic/therapeutic action is recommended after 1 miscarriage. Fetal karyotype is recommended to be obtained after either the second consecutive or third nonconsecutive miscarriage. Products of conception (POC)
Fig. 1. Initial evaluation for early RPL. An algorithm for the initial evaluation of early RPL.
Arrows are provided that guide the reader through various outcomes possible during the
RPL evaluation and appropriate next steps in diagnostic management. (From Brezina PR,
Kutteh WH. Recurrent early pregnancy loss. In: Falcone T, Hurd W, editors. Clinical reproductive medicine and surgery: a practical guide. 2nd edition. New York: Springer; 2013; with
permission.)
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Fig. 2. Workup for early RPL. An algorithm for the full workup of early RPL. Arrows are provided that guide the reader through various outcomes possible during the RPL evaluation
and appropriate next steps in diagnostic and therapeutic management. (From Brezina PR,
Kutteh WH. Recurrent early pregnancy loss. In: Falcone T, Hurd W, editors. Clinical reproductive medicine and surgery: a practical guide. 2nd edition. New York: Springer; 2013; with
permission.)
Table 1
Diagnosis and management of RPL
Cause
Diagnostic Evaluation
Therapy
Genetic
Karyotype partners
Karyotype products of conception
Genetic counseling
Donor gametes, preimplantation
genetic diagnosis
Anatomic
Hysterosalpingography
Hysteroscopy
Sonohysterography
Transvaginal three-dimensional
ultrasonography
Septum transection
Myomectomy
Lysis of adhesions
Endocrinologic
Midluteal progesterone
Thyroid-stimulating hormone
Prolactin
Hemoglobin A1C
Progesterone
Levothyroxine
Bromocriptine, dostinex
Metformin
Immunologic
Lupus anticoagulant
Antiphospholipid antibodies
Anti-b2 glycoprotein
Aspirin
Heparin 1 aspirin
Psychological
Interview
Support groups
Iatrogenic
Tobacco, alcohol use, obesity
Exposure to toxins, chemicals
Eliminate consumption
Eliminate exposure
Management of Early Pregnancy Loss
to send for karyotype may be obtained from early nonviable pregnancies either via
traditional dilation and curettage. POC may be sent for traditional karyotype or, as
we recommend, be sent for 23 chromosome pair microarray evaluation.
The results of this POC karyotype guide further evaluation. If the POC are found to
be aneuploid, no further evaluation or treatment is recommended at that juncture,
because the cause for the loss is known, although all future early miscarriages should
also be subject to karyotypic evaluation. If an unbalanced chromosomal translocation
or inversion is identified in the fetal POC, then the workup focuses on performing
parental karyotypes and offering appropriate therapeutic options, such as preimplantation genetic testing. If the fetal POC are found to be chromosomally normal, then a
full RPL workup is to be performed. If the fetal POC karyotypes have not been performed, then we recommend a full RPL workup after at least 2 consecutive miscarriages or at least 3 nonconsecutive miscarriages. The full RPL workup is outlined in
Fig. 2.
What constitutes a full RPL is a topic of debate. We recommend including an
anatomic evaluation, endocrinologic evaluation, testing for autoimmune factors, evaluating lifestyle and environmental factors, and obtaining parental karyotypes if the
karyotypic status of previous POC is unknown. Not included in this evaluation are
more controversial types of testing and therapies such as those dealing with microbiological factors, thrombophilic factors, immunotherapy, and other evaluations,
although these may be appropriate in certain clinical situations. In the following sections, the physiologic background, diagnostic approaches, and therapy for the various
components of our proposed RPL workup are described. In addition, other more
controversial proposed causes of RPL are addressed (Box 1).
ANATOMIC CAUSES OF RPL
Anatomic causes of RPL are typically diagnosed using hysterosalpingography (HSG)
or sonohysterography. Hysteroscopy, laparoscopy, or magnetic resonance imaging
can supplement these tests as needed. Recently, transvaginal three-dimensional ultrasonography has been introduced and has allowed an accurate and noninvasive
diagnosis of congenital uterine anomalies. The treatment of congenital and acquired
uterine anomalies often involves corrective surgery (Box 2).
Congenital Malformations
Congenital malformations of the reproductive tract result from failure to complete
bilateral duct elongation, fusion, canalization, or septal resorption of the müllerian
Box 1
Pearls
1. A complete evaluation for RPL shows possible causes in 60% of cases.
2. The complete evaluation (genetic, endocrinologic, anatomic, immunologic, and iatrogenic)
should be initiated when the decision to evaluate a couple is made.
3. Couples with primary RPL have identifiable causes just as frequently as couples with
secondary RPL; therefore, all couples should be evaluated.
4. Women with 2 losses have identifiable problems just as frequently as women with 3 or more
losses; thus, evaluation for causes may be initiated after 2 losses.
5. If no cause is identified after a complete evaluation, 65% of couples have a successful
subsequent pregnancy.
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Box 2
Anatomic causes of RPL
1. Congenital malformations of the reproductive tract
2. Intrauterine adhesions
3. Intrauterine masses, including fibroids or polyps
4. Incompetent cervix
ducts. Müllerian anomalies were found in 8% to 10% of women who had had 3 or
more consecutive spontaneous abortions who underwent HSG or hysteroscopic examination of their uteri.3,4,17 Inadequate vascularity compromising the developing
placenta and reduced intraluminal volume have been theorized as possible mechanisms leading to pregnancy loss.
The most common congenital abnormality associated with pregnancy loss is the
septate uterus.18 The spontaneous abortion rate is high, averaging about 65% of pregnancies in some studies.19 A septum is primarily composed of fibromuscular tissue,
which is poorly vascularized. This lack of vascularization may compromise decidual
and placental growth. Alternatively, a uterine septum may impair fetal growth as a
result of reduced endometrial capacity or a distorted endometrial cavity.19 Uncontrolled studies suggest that resection of the uterine septum results in higher delivery
rates than in women without treatment. Other congenital abnormalities, such as uterine didelphys and bicornuate and unicornuate uterus, are more frequently associated
with later trimester losses or preterm delivery.
Intrauterine Adhesions
Intrauterine trauma resulting from endometrial curettage or endometritis is associated
with a risk for the development of adhesions. Intrauterine adhesions (synechiae) are an
acquired uterine defect, which has been associated with recurrent miscarriage. The
severity of adhesions may range form minimal to complete ablation of the endometrial
cavity. The term Asherman syndrome is often used to describe intrauterine adhesions
associated with oligomenorrhea or amenorrhea. These adhesions are believed to
interfere with the normal placentation and are treated with hysteroscopic resection.
The insertion of an intrauterine balloon catheter for 1 week is recommended by
some physicians after resection of synechiae to help prevent reformation of adhesions. During this time, antibiotic prophylaxis with doxycycline (100 mg twice a day)
is given to prevent endometritis. Patients may also be given estrogen and progestin
for 1 month.
Intrauterine Masses
Intrauterine cavity abnormalities, such as submucosal leiomyomas and polyps, can
contribute to pregnancy loss. Depending on the leiomyoma size and location, it may
partially obliterate or alter the contour of the intrauterine cavity, providing a poorly vascularized endometrium for implantation or otherwise compromising placental development. Uterine leiomyomas and polyps may also act like an intrauterine device,
causing subacute endometritis. Until recently, it was believed that only submucous
leiomyomas should be surgically removed before subsequent attempts at pregnancy.
However, several recent studies investigating the implantation rate in women undergoing in vitro fertilization (IVF) have clearly shown decreased implantation, with
Management of Early Pregnancy Loss
intramural leiomyomas in the range of 30 mm.20 When smaller leiomyomas are identified, it is unclear if myomectomy is beneficial.21
Incompetence Cervix
Cervical incompetence can be considered as an acquired uterine anomaly that is
associated with RPL. The diagnosis of cervical incompetence is based on the presence of painless cervical dilation, resulting in the inability of the uterine cervix to retain
a pregnancy. Cervical incompetence commonly causes pregnancy loss in the second,
rather than first, trimester. It may be associated with congenital uterine abnormalities,
such as septate or bicornuate uterus. It is postulated that most cases occur as a result
of surgical trauma to the cervix from conization, loop electrosurgical excision procedures, overdilation of the cervix during pregnancy termination, or obstetric
lacerations.22
ENDOCRINOLOGIC CAUSES OF RPL
Endocrine factors may contribute to 8% to 12% of RPL. Therefore, an endocrinologic
evaluation is a critical component of the RPL workup (Box 3).
Luteal Phase Deficiency
Maintenance of early pregnancy depends on the production of progesterone by the
corpus luteum. Between 7 and 9 weeks of gestation, the developing placenta takes
over the progesterone production. Luteal phase deficiency (LPD) is defined as an
inability of the corpus luteum to secrete progesterone in high enough amounts or
for too short a duration. The preponderance of evidence suggests that LPD is a preovulatory event most likely linked to an alteration in the preovulatory estrogen stimulation, which may indicate poor oocyte quality and a poorly functioning corpus
luteum.23,24 Classically, the diagnosis is based on results of endometrial biopsy,
although this is not recommended as a diagnostic modality. Most investigators advocate the measurement of serum progesterone levels in the luteal phase for the diagnosis of LPD, with levels lower than 10 ng/mL considered abnormal.25 However,
progesterone levels are subject to large fluctuations because of pulsatile release of
the luteinizing hormone (LH). Moreover, there is a lack of correlation between serum
levels of progesterone and endometrial histology.26 Although conflicting data exist,
a recent Cochrane review evaluating 15 trials concluded that there was a benefit to
the routine administration of progesterone to all women with a history of RPL.27,28 Progesterone is available either as intravaginal suppositories (50–100 mg twice daily starting the third day after LH surge and continuing for 8–10 weeks) or as intramuscular (IM)
injections (50 mg IM daily).
Box 3
Endocrinologic causes of RPL
1. Luteal phase deficiency
2. Untreated hypothyroidism
3. Abnormal glucose metabolism
4. Hyperprolactinemia
5. Diminished ovarian reserve
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Untreated Hypothyroidism
Untreated hypothyroidism may increase the risk of miscarriage. A study of more than
700 patients with RPL identified 7.6% with hypothyroidism.29 Hypothyroidism is easily
diagnosed with a sensitive thyroid-stimulating hormone (TSH) test, and patients
should be treated to become euthyroid (defined for the purposes of RPL as between
1.0 and 2.5 uIU/mL) before attempting a next pregnancy.1,30 It has also been suggested that thyroid antibodies are increased in women with RPL. A retrospective study
of 700 patients with RPL31 showed that 158 women had antithyroid antibodies but only
23 of those women had clinical hypothyroidism from an abnormal TSH value. The
presence of antithyroid antibodies may imply abnormal T-cell function, and therefore,
more of an immune dysfunction rather than an endocrine disorder may be responsible
for the pregnancy losses. The Endocrine Society recommends that patients with RPL
be treated to keep a TSH level of between 1.0 and 2.5 uIU/mL in the first trimester.30
For TSH levels found to be between 2.5 and 10 mIU/mL, a starting levothyroxine dose
of at least 50 mg/d is recommended.30
Abnormal Glucose Metabolism
Patients with poorly controlled diabetes are known to have an increased risk of spontaneous miscarriage, which is reduced to normal spontaneous loss rates when women
are euglycemic preconceptually.32 Testing for fasting insulin and glucose is simple,
and treatment with insulin-sensitizing agents can reduce the risk of recurrent miscarriage.33 More recently, determining the average load of blood glucose through testing
of hemoglobin A1C has become an increasingly used modality to evaluate insulin resistance.1 Because there is strong evidence that obesity or insulin resistance is associated with an increased risk of miscarriage, weight reduction in obese women is a first
step in the treatment. Metformin seems to improve pregnancy outcome, but the evidence for this treatment is limited to a few cohort studies. Metformin is a category
B medication in the first trimester of pregnancy and seems to be safe. Other endocrine
abnormalities, such as thyroid disorders and diabetes, should be corrected before
conception.
Hyperprolactinemia
Normal circulating levels of prolactin may play an important role in maintaining early
pregnancy. Data from animal studies suggest that increased prolactin levels may
adversely affect corpus luteal function; however, this concept has not been proved
in humans.34 A recent study of 64 hyperprolactinemic women showed that bromocriptine therapy was associated with a higher rate of successful pregnancy and that prolactin levels were significantly higher in women who miscarried.35
Diminished Ovarian Reserve
Follicle stimulating hormone (FSH) is believed to be a marker of the number of follicles
available for recruitment on any given menstrual cycle. Therefore, increased levels of
FSH in the early follicular phase of the menstrual cycle are representative of diminished ovarian reserve; a condition in which a low number of follicular units are available
for recruitment. More recently, other markers, such as decreased anti-müllerian hormone, have been introduced to identify diminished ovarian reserve. Although the frequency of increased day 3 FSH levels in women with recurrent miscarriage is similar to
the frequency in the infertile population, the prognosis of recurrent miscarriages is
worsened with increased day 3 FSH levels.36 Although no treatment is available,
Management of Early Pregnancy Loss
testing may be helpful in women older than 35 years with RPL, and appropriate counseling should follow.
AUTOIMMUNE/THROMBOTIC FACTORS AS THE CAUSE OF RPL
Immunologic Disorders
Autoimmune factors: maternal response to self
In some instances, there is a failure in normal control mechanisms that prevent an immune reaction against self, resulting in an autoimmune response (Box 4).37 Autoantibodies to phospholipids, thyroid antigens, nuclear antigens, and others have been
investigated as possible causes for pregnancy loss.29 aPL antibodies include the
lupus anticoagulant, anti-b2 glycoprotein I antibodies, and anticardiolipin antibodies.
There is still controversy concerning testing for other phospholipids, but an increasing
number of studies suggest that antibodies to phosphatidyl serine are also associated
with pregnancy loss.38 Women with systemic lupus erythematosus and aPL antibodies have increased risks for miscarriage compared with those with lupus and
negative aPL antibodies.39
Antiphospholipid Antibody Syndrome
Antiphospholipid antibody syndrome (APS) is an autoimmune condition characterized
by the production of moderate to high levels of aPL antibodies and certain clinical features (Table 2).40 The presence of aPL antibodies (anticardiolipin and lupus anticoagulant) during pregnancy is a major risk factor for adverse pregnancy outcome.41 In a
large meta-analysis of studies of couples with recurrent abortion, the incidence of
APS was between 15% and 20% compared with about 5% in nonpregnant women
without a history of obstetric complications.42,43
Several mechanisms have been proposed by which aPL antibodies might mediate
pregnancy loss. Classically, it was believed that aPL antibodies induced thromboses
in vessels surrounding the placental-maternal unit, resulting in placental infarction and
fetal death. However, recent data have suggested that the primary mechanism by
which aPL antibodies lead to miscarriage may be via a deleterious effect conferred
directly on trophoblastic cells or endothelial cells.44,45 aPL antibodies can interact
with cultured human vascular endothelial cells with resultant injury or activation.44
Furthermore, aPL antibodies have been shown to inhibit secretion of human placental
chorionic gonadotropin and to inhibit the expression of trophoblast cell adhesion molecules (a1 and a5 integrins, E and VE cadherins).45 These mechanisms could explain
RPL secondary to aPL antibodies early in the first trimester.42,46,47
APS is treated with a combination of low-dose heparin (5000–10,000 units subcutaneously every 12 hours), and low-dose aspirin (81 mg by mouth daily) seems to be
effective and may reduce pregnancy loss by 54% in women with APS.42,46,47 Aspirin
alone does not seem to reduce miscarriage rates.48 Unfractionated heparin is
preferred to low-molecular-weight heparin, based on available data.49
Box 4
Autoimmune factors as the cause of RPL
1. Antiphospholipid antibody syndrome
a. Anticardiolipin antibodies
b. Lupus anticoagulant
c. b2 Glycoprotein antibodies
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Table 2
Clinical and laboratory characteristics of antiphospholipid antibody syndrome
Clinical
Laboratory
Pregnancy morbidity
IgG anticardiolipina
1 unexplained death at 10 wk or
IgM anticardiolipina
Delivery at 34 wk with severe pregnancy-induced
hypertension or
Positive lupus anticoagulant test
3 losses before 10 wk
IgG anti-b2 glycoprotein 1a
Thrombosis
IgM anti-b2 glycoprotein 1a
Venous
—
Arterial, including stroke
—
Patients should have at least 1 clinical and 1 laboratory feature at some time in the course of their
disease. Laboratory tests should be positive on at least 2 occasions.
a
99th percentile.
Modified from Miyakis S, Lockshin MD, Atsumi T, et al. International consensus statement on an
update of the classification criteria for definite antiphospholipid syndrome (APS). J Thromb Haemost 2006;4:295–306; with permission.
Treatment with steroids is not recommended based on current evidence.42,50
Aspirin should be started preconceptually, and heparin should be started after the first
positive pregnancy test.46 Treatment should be continued until the time of delivery,
because these women are at an increased risk for thrombosis. Postpartum thromboprophylaxis is reasonable for a short interval to prevent thrombosis when the risk is
high.43 The adverse reactions associated with heparin include bleeding, thrombocytopenia, and osteoporosis with fracture. Calcium (600 mg twice daily) with added
vitamin D supplementation (400 IU daily) and weight-bearing exercise are encouraged
to decrease the risk of osteoporosis. In any pregnant woman starting on heparin, the
platelet count should be monitored weekly for the first 2 weeks after initiation, and after
any dosage change. Women with APS should consider avoiding the use of estrogencontaining oral contraceptives in the future.51
Immunotherapy
Immunotherapy for alloimmune disorders is based on the hypothesis that spontaneous abortion occurs because of a failure of maternal immunologic adaptation to
the developing conceptus, resulting in a form of transplantation rejection. Although
some randomized double-blind studies have shown an increase with therapies such
as paternal leukocyte immunization, trophoblast immune infusion, intravenous intralipid therapy, and immunoglobulin infusion in successful pregnancy outcomes, other
have not confirmed these results.51–53 A Cochrane review of 19 trials of various forms
of immunotherapy54 did not show significant differences between treatment and control groups. There is insufficient evidence to recommend the use of these therapies for
RPL. Testing for TH1 and TH2 profiles, parental HLA profiles, alloantibodies, natural
killer cells, antiparental cytotoxic antibodies, or embryotoxic factor assessment are
not clinically justified.
Antinuclear Antibodies
Approximately 10% to 15% of all women have detectable antinuclear antibodies,
regardless of their history of pregnancy loss. Their chance of successful pregnancy
outcome is not dependent on the presence or absence of antinuclear antibodies.
Management of Early Pregnancy Loss
Treatments such as steroids have been shown to increase the maternal and fetal complications without benefiting live births.55 Thus, routine testing and treatment of antinuclear antibodies are not indicated.
Microbiological
Certain infectious agents have been identified more frequently in cultures from women
who have had spontaneous pregnancy losses.56 These agents include Ureaplasma
urealyticum, Mycoplasma hominis, and Chlamydia. Other less frequent pathogens
include Toxoplasma gondii, rubella, herpes simplex virus, measles, cytomegalovirus,
coxsackievirus, and Listeria monocytogenes. None of these pathogens has been
causally linked to RPL. Because of the association with sporadic pregnancy losses
and the ease of diagnosis, some clinicians test women with RPL and treat for the
appropriate pathogen in both parents.
Appropriate antibiotic therapy should be instituted in both parents when cervical infections are identified. Infections with Mycoplasma, Ureaplasma, and Chlamydia are
treated with doxycycline, 100 mg twice daily by mouth for 14 days. For those who
fail treatment based on a test of cure culture, the options are to extend treatment of
both partners to 30 days or to use ofloxacin 300 mg daily for 14 days for both partners.
Thrombotic Disorders
Thrombophilias are believed to be responsible for more than half of maternal venous
thromboembolisms in pregnancy; however, ACOG recommends that only patients
with a personal or family history of thromboembolic events should be tested.57
The recommended evaluations are:
a. Factor V Leiden screening with activated protein C (APC) resistance using a
second-generation coagulation assay is probably the most cost-effective
approach. Patients with a low APC resistance ratio (<2.0) should then be genotyped for the factor V Leiden mutation
b. Prothrombin G20210A gene mutation using polymerase chain reaction
c. Antithrombin activity with normal levels between 75% and 130%
d. Protein S activity with normal levels between 60% and 145%
e. Protein C activity with normal levels between 75% and 150%
GENETIC FACTORS AS THE CAUSE OF RPL
There are a variety of genetic factors that may result in failure of a pregnancy to
develop. These factors include aneuploidy (the gain or loss of a chromosome), chromosomal imbalances as a result of parentally harbored translocations or inversions,
deletions or duplications of genetic information within chromosomes, and singlegene mutations. Broadly, genetic factors may be divided into embryonic errors
derived from known parental chromosomal abnormalities and embryonic errors that
arise de novo in apparently chromosomally normal parents.
Parental Chromosomal Disorders
Parental chromosome anomalies occur in 3% to 5% of couples with RPL as opposed
to 0.7% in the general population. These anomalies include translocations, inversions,
and the rare ring chromosomes. Balanced translocations are the most common chromosomal abnormalities contributing to RPL.58 Chromosomal abnormality in 1 of the
parents can be found in up to 3% to 5% of couples who experience multiple spontaneous abortions. If no fetal POC are available and the couple have a history of at least
2 consecutive or 3 nonconsecutive fetal losses, we recommend obtaining parental
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Brezina & Kutteh
karyotypes. Treatment of parental balanced chromosomal translocations/inversions
may be addressed through preimplantation genetic testing, which is addressed later
in this article.
Recurrent Aneuploidy
The first chromosomally abnormal abortus was documented in 1961, and since then, a
large body of data on the chromosomal status of spontaneous abortuses has accumulated. The overall frequency of chromosome abnormalities in spontaneous abortions is
at least 50%.14,59–62
Developmental Errors in Euploid Embryos
Another cause of first-trimester miscarriage seems to be failure of chromosomally
}llerian agenesis are
normal embryos to develop properly. Much as women with mu
chromosomally normal but have a separate developmental abnormality, serious
developmental abnormalities that involve vital structures may result in euploid embryos. Small studies have suggested that the rates of significant anatomic abnormalities in chromosomally normal embryos taken from first-trimester miscarriages in
women with RPL may exceed 25%.63
Preimplantation Genetic Testing
Genetic causes of RPL may be subdivided into embryo abnormalities that are the
result of known parental abnormalities (such as parental balanced translocations or inversions) and embryo aneuploidy in parents believed to be chromosomally normal.
Preimplantation genetic testing is a technology that is designed to minimize the effects
of these and other embryonic genetic abnormalities. Preimplantation genetic testing is
accomplished by performing an IVF cycle, removing a cell(s) from the resultant embryos or oocytes, evaluating this cell for genetic abnormalities, and using the results
to determine which embryos are ideal for uterine transfer. When a known parental genetic abnormality is identified, as in parental balanced translocations, this practice is
referred to as preimplantation genetic diagnosis (PGD). When this process is executed
to determine which embryos are aneuploid in parents believed to be chromosomally
normal, the procedure is referred to as preimplantation genetic screening (PGS).
PGD for structural aberrations such as translocations and inversions is a generally
accepted use of preimplantation genetic testing. In contrast, PGS is more controversial. A 2007 publication in the New England Journal of Medicine by Mastenbroek and
colleagues64 showed no benefit to PGS. This study was followed by major medical societies discouraging the routine use of PGS.65 Since this time, newer technologies,
such as microarrays, have been introduced, which are capable of evaluating the ploidy
status of all 23 pairs of chromosomes instead of the 9 to 14 pairs of chromosomes
evaluated with older fluorescence in situ hybridization technologies.66 In addition, performing embryo biopsy at the blastocyst, as opposed to the cleavage, stage seems to
confer superior pregnancy rates.67,68 Although recent data evaluating pregnancy rates
in RPL patients using 23 chromosome microarrays are encouraging, the routine use of
this technology remains controversial.69,70
LIFESTYLE ISSUES AND ENVIRONMENTAL TOXINS
Couples experiencing RPL are often concerned that those toxins within the environment may have contributed to their reproductive difficulty. It is important that health
care providers, counseling patients about exposures to substances in the environment, have current and accurate information in order to respond to these concerns.
Management of Early Pregnancy Loss
Cigarette Smoking
Cigarette smoking reduces fertility and increases the rate of spontaneous abortion.
The data evaluating smoking and miscarriage are extensive and involve approximately
100,000 individuals. The studies suggest a clinically significant detrimental effect of
cigarette smoking, which is dose dependent, with a relative risk for miscarriage among
moderate smokers (10–20 cigarettes a day) being 1.1 to 1.3.71 Patients should be
aggressively counseled to stop cigarette smoking before attempting pregnancy.
Alcohol Consumption
Alcohol consumption is associated with a risk of spontaneous abortion.72 The minimum threshold dose for significantly increasing the risk of first-trimester miscarriage
seems to be 2 or more alcoholic drinks per week.73,74 When personal habits, cigarette
smoking, and alcohol are used in the same individual, the risk of pregnancy loss may
increase 4-fold. Couples should be counseled concerning these habits and strongly
encouraged to discontinue these before attempting subsequent conception.75
Obesity
Obesity, defined as a body mass index (BMI, calculated as weight in kilograms divided
by the square of height in meters) greater than 30, has been associated with an
increased risk of miscarriage. Obesity (BMI>30 kg/m2) has been shown to be an independent risk factor for first-trimester miscarriage.24 The association is strongest in
women with BMI greater than 40. The cause of this phenomenon is unclear. However,
many studies have linked obesity to a generalized increase in systemic inflammatory
responses.76
Caffeine Intake
Several studies have shown that caffeine in excess of 300 mg/d (>2 cups of coffee per
day) is associated with a modest increase in spontaneous abortion, but it is not clear if
this relationship is causal.77
Ionizing Radiation
The studies of atomic bomb survivors in Japan showed that in utero exposure to highdose radiation increased the risk of spontaneous abortions, premature deliveries, and
stillbirths.78 Diagnostic radiographs in the first trimester delivering less than 5 rad are
not teratogenic.79,80 However, large doses (360–500 rad), used in therapeutic radiation, induce abortion in offspring exposed in utero in most cases. Adverse effects of
chronic low-dose radiation on reproduction have not been identified in humans.80
OUTCOME
The treatment of RPL should be directed at the cause. Given the good outcome for
most couples with unexplained recurrent abortion in the absence of treatment, it is
difficult to recommend unproven therapies, especially if they are invasive and expensive. Explanation and appropriate emotional support are possibly the 2 most important aspects of therapy. In 1 study,17 antenatal counseling and psychological
support for couples with recurrent abortion and no abnormal findings resulted in a
pregnancy success rate of 86% compared with a success rate of 33% for women
who were given no specific antenatal care.
In approximately 60% of all cases of RPL, a complete evaluation shows a possible
cause.3,4 Abnormal findings during the evaluation should be corrected before attempting any subsequent pregnancy. If no cause can be found, most couples have a
13
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Brezina & Kutteh
successful pregnancy outcome with supportive therapy alone.73 Once a pregnancy
occurs, the patient should be monitored closely, with evaluation of quantitative hCG
levels at least twice and documentation of adequate progesterone levels. Early sonography should be scheduled, and any encouraging results should be communicated to
the couple. In women with a history of RPL, the presence of a normal embryonic heart
rate between 6 and 8 gestational weeks that is confirmed with repeat sonography in
1 week is associated with a live birth rate of 82%.81,82
Couples who have experienced RPL want to know what caused the miscarriage.
Unexplained reproductive failure can lead to anger, guilt, and depression. Anger
may be directed toward their physician for not being able to solve their reproductive
problems. Feelings of grief and guilt after an early loss are often as intense as those
after a stillbirth, and parents experience a grief reaction similar to those associated
with the death of an adult. The couple should be assured that exercise, intercourse,
and dietary indiscretions do not cause miscarriage. Any questions or concerns that
the couple may have about personal habits should be discussed.
The prognosis for women with RPL to deliver with medical therapy is good. A recent
study5 evaluating 987 women with RPL found that the chances of achieving a live birth
within 5 years of initial physician consultation was in excess of 80% for women
younger than 30 years and approximately 60% to 70% for women aged 31 to 40 years.
Women who suffer RPL have already begun to prepare for their baby, both emotionally and physically, compared with couples with infertility who have never conceived.
When a miscarriage occurs, a couple may have great difficulty informing friends or
family about the loss. Feelings of hopelessness may continue long after the loss. Patients may continue to grieve and have episodes of depression on the expected due
date or the date of the pregnancy loss. Participation in support groups or referral for
grief counseling may be beneficial in many cases (SHARE, Pregnancy and Infant
Loss Support, http://www.nationalshare.com/).
ACKNOWLEDGMENTS
We thank Drs Raymond Ke and Jianchi Ding for their help with the writing of this
article.
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R e s e a rc h M e t h o d o l o g y i n
R e c u r re n t Preg n a n c y L o s s
Ole B. Christiansen,
MD, DMSc
a,b,
*
KEYWORDS
Recurrent pregnancy loss Recurrent miscarriage Medical research
Research studies Methodological flaws
KEY POINTS
There is currently substantial disagreement concerning the diagnostic criteria for recurrent
pregnancy loss (RPL), which renders comparisons between research studies in the area
difficult.
There are numerous methodological pitfalls that threaten the validity of research studies in
the field of RPL and it is necessary for scientists and clinicians to be aware of them.
Some of the methodological pitfalls are common for medical research in general, whereas
some are specific for RPL research.
Frequently seen methodological flaws in case-control studies are comparisons of biomarkers between patients with RPL and controls that differ from patients with regard to
previous ongoing pregnancies, relevant endocrine factors, and viability of the fetal tissue
at the time of sampling.
In cohort studies, incomplete follow-up of patients in many studies has resulted in huge
variations in estimates of the prognosis after RPL.
Only a few small and heterogeneous double-blinded placebo-controlled trials of treatments of RPL have been carried out with very heterogeneous results.
Proposals are given for improvements in the design of research studies in RPL that hopefully can improve the quality of studies in the future.
INTRODUCTION
Compared with the situation in other reproductive medicine disorders, such as tubal or
male factor infertility and in other areas of medicine, there is very little consensus
about which investigations are useful for identifying causes or estimating the prognosis and which treatments are effective in recurrent pregnancy loss (RPL). It is generally agreed that when the tubes are occluded, as diagnosed by laparoscopy or
a
Fertility Clinic 4071, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, DK-2100,
Copenhagen, Denmark; b Department of Obstetrics and Gynecology, Aalborg University Hospital, Reberbansgade, DK-9000, Aalborg, Denmark
* Fertility Clinic 4071, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, DK-2100,
Copenhagen, Denmark.
E-mail address: olbc@rn.dk
Obstet Gynecol Clin N Am 41 (2014) 19–39
http://dx.doi.org/10.1016/j.ogc.2013.10.001
obgyn.theclinics.com
0889-8545/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
20
Christiansen
hysterosalpingography (HSG), pregnancy can happen only after in vitro fertilization
(IVF), and when the number of viable spermatozoa is very low, pregnancy can happen
only after intracytoplasmatic sperm injection (ICSI). It is also generally agreed that
IVF or ICSI are very efficient treatment methods for the 2 reproductive disorders. In
recurrent early pregnancy loss there is much more disagreement about diagnosis,
cause, and treatments. Although most guidelines from specialist societies do not support the screening of RPL women for hereditary thrombophilia factors or peripheral
blood or endometrial natural killer (NK) cell numbers and function,1–3 many clinics
are still doing this, and whereas the Cochrane review4 or national guidelines do not
recommend immunotherapy1,2 or preimplantation genetic screening (PGS)5 for RPL,
immunotherapy and PGS are still widely used in many clinics.
There could be many reasons why doctors very often do not adhere to the clinical
guidelines regarding RPL:
Pressure from desperate patients to do something although very few proven
therapies really exist
The doctors’ economical motives, as many patients are desperate and willing to
pay a lot of money for treatments that may provide them with some hope for a
solution to their problem
Current guidelines are based on few, small, and often poor-quality studies that
cannot support strong, evidence-based recommendations
In this author’s view, the third statement is the most important cause for this poor
adherence to RPL guidelines. With regard to almost every diagnostic test or treatment
for RPL, it is possible to find studies presenting data strongly in favor of this test or
treatment and other studies strongly against. It is therefore often up to clinicians themselves to decide which studies they find trustworthy.
The aim of this article is to highlight pitfalls in research methodology that may
explain why studies in RPL often provide very divergent results, and it is hoped that
insight in this issue may help clinicians to decide which published studies are most
valid. It may help researchers to eliminate methodological flaws in future studies,
which may hopefully come to some kind of agreement about the usefulness of diagnostic tests and treatments in RPL.
CONTROVERSIES OF DEFINITION
It is disputed how to define RPL. It is important to realize that RPL is defined quite
differently from most other diseases. Most diseases are defined by some unique pathoanatomical, clinical, or paraclinical findings being permanently present, whereas RPL
is defined by a series of transient events in the past that may have be poorly registered.
The controversies concerning how to define RPL deal with
The number of miscarriages needed for the diagnosis
The role of nonconsecutive miscarriages
The role of preclinical losses
Until 10 years ago, the definition of RPL was undisputedly 3 or more consecutive
miscarriages, because it was commonly agreed that after 3 miscarriages the chance
of live birth the next pregnancy without treatment was substantially decreased.6 However, during the recent years, some national guidelines have adopted an RPL definition
of only 2 clinically recognized miscarriages1 or 2 not necessarily consecutive miscarriages.7 This redefinition is based on finding similar frequencies of selected factors
suggested to cause RPL: uterine abnormalities; antiphosphospholipid antibodies
Research Methodology in Recurrent Pregnancy Loss
(APL); parental chromosome aberrations; or the factor V Leiden mutation in women
with 2, women with 3, and women with more miscarriages.7,8 It is argued that when
such risk factors already recommended in the screening of couples with 3 miscarriages can be found with similar prevalence in those with 2 miscarriages, they should
also be examined in the latter. If the same tests are recommended in couples with 2 as
well as those with 3 or more miscarriages, it is a short step to redefine RPL as 2 or
more miscarriages. There is also now disagreement regarding which kind of pregnancy losses should be included in the criteria for RPL. Thirty years ago, because
of the nonexistence of ultrasonic examinations and high sensitive pregnancy tests,
pregnancies could not be diagnosed before gestational week (GW) 6 to 7; therefore,
the pregnancy losses considered in the RPL diagnosis were miscarriages, which
had normally been confirmed by curettage and histology. Pregnancies can now, owing
to highly sensitive and specific b-human chorionic gonadotropin (hCG) tests, be diagnosed a few days after the due menstrual period, and many of these (biochemical
pregnancies) will fail before it is possible to do transvaginal ultrasound. There is
thus an urgent need to find a place for these kinds of losses in the RPL diagnosis.
Because transiently positive pregnancy tests at the time of the due period are a
frequent finding in women not using anticonception,9 many gynecologists have
been reluctant to include biochemical pregnancies in the RPL diagnosis, and the
American Society for Reproductive Medicine (ASRM) definition of RPL (2 or more clinical miscarriages) completely disregards them.1 A recent study from the European Society for Human Reproduction and Embryology (ESHRE) early pregnancy special
interest group on the other side found that in patients with RPL, each early pregnancy
loss confirmed only by a b-hCG test displays a negative prognostic impact equal to
that of a clinical miscarriage, supporting the view that biochemical pregnancies should
be included in the RPL diagnosis.10 The different diagnostic criteria recommended in
the national guidelines or by leading RPL clinics are1,2,7,10 as follows:
3 consecutive pregnancy losses before 24 weeks of gestation
2 consecutive clinical pregnancy losses
3 consecutive clinical miscarriages and biochemical pregnancies
2 not necessarily consecutive pregnancy losses before 24 weeks of gestation
In numerous studies, it was found that the strongest predictive factor for new
miscarriage in patients with RPL is the number of previous losses.6,11 Because the
same diagnosis, RPL, for the time being covers patients with a wide range of previous losses and therefore very different pregnancy prognoses, it will in the future be
increasingly difficult to compare and combine different studies of outcome in patients with RPL (eg, results of randomized controlled trials [RCTs]). The only way
to overcome this obstacle is that the investigators in such studies stratify the results
according to the number of previous clinical miscarriages, as well as biochemical
pregnancies or pregnancies of unknown location (PULs).
TYPES OF RESEARCH STUDIES
Different pitfalls characterize the 3 main types of research studies done in RPL:
Case-control studies
Cohort studies
Intervention and treatment studies
For each category of studies, I provide an overview of the pitfalls that threaten the
validity of the studies and the flaws often seen in publications: some of them can be
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seen in other areas of medical research and they are discussed superficially, whereas
others that are specific for RPL research are discussed in more detail.
CASE-CONTROL STUDIES
Case-control studies always have a retrospective design. The frequency of a potential risk factor is investigated in a group of patients who have been sampled during a
defined period (typically in a single clinic) with a specific disease diagnosis and
compared with the corresponding frequency in a group of randomly selected individuals either without the disease or (if the disease is rare) selected from the background population. An estimate of the potential risk factors’ association with the
disease is typically given by the odds ratio (OR) with 95% confidence limits indicating
the ratio between the frequency of the risk factor in diseased individuals and in
controls.
Methodological errors in case-control studies can occur during the sampling of both
patients and control subjects and errors can occur in the testing for potential risk
factors.
Flaws in Sampling of Patients and Controls
Inconsistent diagnosis
The different definitions of RPL have already been discussed. Different RPL definitions
will make comparisons between case-control studies originating from regions with
different definitions increasingly difficult in the future.
Misclassification of disease/outcome status
Even if identical RPL definitions are used, patients in different studies can differ
regarding the severity of the disease: the number of previous miscarriages. Because
the RPL diagnosis is based on a series of past events, the validity of the diagnosis is
dependent on the quality of the information that is available about these events. In
many clinics, information about previous pregnancy losses comes primarily from interviewing the patients. Misclassification of disease/outcome status (the number of previous miscarriages) can be random or nonrandom. There are many examples of
random outcome misclassification when dealing with miscarriages. Only 71% of miscarriages reported by women without RPL who have been treated at hospital could
be verified in hospital records,12 and in a retrospective study, 348 women recalled
30 (6%) of 507 miscarriages that were not reported in a prospective study several
years before.13 Random outcome misclassification results in an underestimate of
the hypothesized association between exposure and disease/outcome in casecontrol studies (Table 1).
Retrospective information about previous pregnancy losses can also be subjected
to nonrandom misclassification, also called recall or information bias. This misclassification is a difference in the ability or inclination to remember or report events or exposures in the past in individuals with or without particular characteristics. Women
who had given birth to a child with a congenital malformation will search their memory
extensively for any potentially teratogenic exposures during pregnancy and therefore
retrospectively report more exposures than women who had delivered a healthy child,
although there is no real difference in the frequency of harmful exposures in the
2 groups. Some women with 1 or 2 confirmed miscarriages will be more prone to interpret delayed menstruations or recall previous terminations as miscarriages than
women without recent pregnancy losses, and thus erroneously get a diagnosis of
RPL. Such nonrandom misclassification of disease/outcome status will result in either
an overestimation or underestimation (see Table 1) of the true size of the hypothesized
Research Methodology in Recurrent Pregnancy Loss
Table 1
Important methodological pitfalls typical for research studies in RPL
Factor to Evaluate
Effect on Study Outcome
Definition of RPL 2 miscarriages
Decreases difference between risk variables in
CCS and treatment effect in RCTs
Random misclassification
Decreases difference between risk variables in CCS
Nonrandom misclassification
Decreases or increases difference between risk
variables in CCS or outcome variables in CS
Ascertainment bias
Increases difference between risk variables in CCS
Relevant mismatches between
patients and controls
Increases difference between risk variables in CCS
Lack of protocol details/multiple
testing
Overestimates significance of chance findings
Historical controls
Increases effects in treatment studies
Nonblinding
Increases or decreases treatment effects in RCTs
Premature termination after interim
analysis
Decreases treatment effect in RCTs
Inclusion after detection of fetal heart
action
Decreases treatment effect in RCTs
Poor characterization of RPL and
subgroups of RPL
Renders comparisons between CCS and RCTs
difficult and makes meta-analysis difficult
Unfounded exclusions of RCTs in
systematic reviews
Bias combined risk estimates in meta-analyses
Abbreviations: CCS, case-control study; RCT, randomized controlled trial; RPL, recurrent pregnancy
loss.
relationship between exposure and disease/outcome (RPL). To avoid random and
nonrandom misclassification in RPL case-control studies, information about previous
pregnancies should as much as possible be confirmed from external sources: records
from hospitals, fertility clinics, and practitioners and serum hCG measurements should
be documented from laboratory reports.
Ascertainment bias
In case-control studies, the frequency of a potential risk factor for the disorder under
study (eg, RPL) is compared between patients and controls. Ascertainment or selection bias happens when patients with some clinical or paraclinical risk factor are preferentially referred to a specific clinic because of knowledge of the clinic’s expertise
or interest, and a study focusing on this particular risk factor is undertaken in the
clinic. An example of ascertainment bias in RPL has been reported by Out and colleagues.14 In this study, the frequency of the APLs anticardiolipin and lupus anticoagulant was higher in patients with RPL referred to a Dutch center for APL research
than in controls. However, when patients with RPL with a history of thromboembolic
or lupuslike symptoms were excluded, the prevalence of APL in the remaining patients with RPL did not differ from that of controls. The high prevalence of APL in
the total group of patients resulted from the preferential referral of patients with
RPL with APL-associated symptoms to the clinic due to its special expertise (see
Table 1).
Ascertainment bias can also work in controls. In studies of risk factors for adverse
pregnancy outcome, information is often obtained or blood samples drawn from
women with healthy pregnancies coming for routine pregnancy control. Women giving
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informed consent to become controls are often better educated than average women,
thereby decreasing the occurrence of lifestyle factors and exposures that may be
harmful in pregnancy. When staff members or healthy blood donors are used as controls, these also undergo positive selection for being healthier than the average
population.
Flaws in Estimating Risk Factors
Misclassification of exposure status
If the risk factor(s) under study is a potentially harmful exposure (eg, infection, smoking, medicamentation) in which the estimate of exposure is based on information
retrospectively obtained from the patients and controls themselves; as previously discussed, this information can be subject to both random and nonrandom misclassification. If exposures have the same probability of being overreported/underreported in
patients and controls, we are dealing with random misclassification and this will
lead to an underestimate of the hypothesized relationship between exposure and disease/outcome. When the probability of exposure misclassification differs between patients and controls, nonrandom misclassification occurs. An example of nonrandom
misclassification is when patients with RPL often recall an episode of fever during a
pregnancy that subsequently failed, whereas controls with successful pregnancies
report such episodes less often, although the incidence of fever in the 2 groups
may be similar. Nonrandom misclassification of exposures can lead to an underestimate or overestimate of the true size of association between exposure and disease/
outcome. To avoid misclassification in RPL case-control studies, data about exposures should be collected as much as possible from external sources: records from
hospitals or practitioners or be collected before the outcome is known: in early pregnancy before miscarriage is diagnosed.
Confounding
In case-control studies, a confounding factor is a clinical or paraclinical factor that is
associated with both the risk factor and the disease/outcome under study. If adequate
measures are not taken, a confounding factor can be mistaken as a causal factor or
diminish the estimate of the impact (OR) of the risk factor under study. In RPL studies,
age is an important and common confounding factor. In studies of the prevalence of
autoantibodies in patients with RPL and controls, age is associated with both the risk
of miscarriage and RPL and the occurrence of autoantibodies. Elimination of the confounding effect of age during the inclusion phase of such studies can be undertaken by
age-matching patients and controls and in the analysis phase by reporting autoantibody frequencies in different age strata of patients and controls and subsequently
do adjustment by multivariate statistical methods.
Mismatch between patient and controls group
In case-control studies, the aim is to compare diseased and healthy individuals, which
is quite straightforward regarding most diseases, but in RPL, research finding a suitable control group is a much more complex task (see Table 1; Table 2). Case-control
studies in RPL research typically compare the following:
Biomarkers in the blood or endometrium of nonpregnant women or in the blood
of pregnant patients with RPL with the same biomarkers in women who do not
have RPL
Biomarkers in decidual or trophoblast tissue from women with RPL who have
miscarried with the same biomarkers in tissue from non-RPL women who had
an induced abortion.
Table 2
Suggested optimal control groups for the investigation of biomarkers in patients with RPL or their products of conception
Genetic
Biomarkers
Nongenetic Biomarkers
Peripheral Blood
Luteal Phase Endometrium
Decidual/Trophoblast Tissue
Peripheral Blood/
Tissue
Controlsa
RPLb
Controlsb
RPLc
Controlsc
RPL
Controls
Primary/NP
Nulligravida/NP
Primary
Nulligravida
Primary,
Euploid male embryo
Primary RPL
Aneuploid embryo
All
Multipara
Secondary/NP
Previous birth/NP
Secondary
Previous birth
Secondary,
Euploid male embryo
Secondary RPL
Aneuploid embryo
Primary GW5
Primigravida GW5
Secondary GW5
Previous birth GW5
Primary > GW6
Euploid male embryo
Primary RPL > GW6
Aneuploid embryo
Secondary > GW6
Euploid male embryo
Secondary RPL > GW6
Aneuploid embryo
In each double column, the suggested optimal controls are found to the right of the RPL column.
Abbreviations: GW, gestational week calculated from the first day of last menstrual period; NP, not pregnant; RPL, recurrent pregnancy loss.
a,b,c
Women in each comparable pair should ideally have similar estrogen and progesterone levels in the nonpregnant state and similar hCG, estrogen, and progesterone levels in the pregnant state.
Research Methodology in Recurrent Pregnancy Loss
RPLa
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In studies of external exposures or genetic biomarkers, the ideal control group for
patients with RPL is women with proven fertility: typically women with 2 or more uncomplicated births and no miscarriages, as genetic polymorphisms will not change
according to reproductive history or be affected by endocrine factors or inflammation
(see Table 2).
However, it is much more complex to identify the ideal controls for the investigation
of nongenetically determined biomarkers in the blood, the endometrium, or trophoblast tissue. Some biomarkers, although exhibiting no impact on pregnancy outcome,
may be different in patients with RPL and women with previous births merely because
of their different reproductive histories.
An illustrative example is anti-HLA antibodies and studies of their role in RPL.
Several years ago many articles reported that these antibodies could be detected
much less frequently in the blood of patients with primary RPL (no previous ongoing
pregnancies) than in control women who had previously given birth. It was postulated
that lack of these “blocking antibodies” was a cause of the RPL and that deliberate
immunization of the patients with paternal lymphocytes with the aim to stimulate antibody production would improve the pregnancy prognosis. It is now generally recognized that these antibodies are a common feature of normal ongoing pregnancy
due to passage of fetal cells through the placenta into the maternal circulation during
late pregnancy and they often persist for many years.15 Therefore, it is not surprising
that patients with primary RPL normally lack these antibodies, whereas multipara are
often positive.
It has also been shown that cellular immunity is being permanently changed after a
birth. Clones of cytotoxic lymphocytes with specificity for male-specific minor histocompatibility (HY) antigens develop in half of the women pregnant with a male fetus and the
anti-HY cytotoxicity remains unchanged up to 18 years after delivery.16 Long-term
persistence of regulatory T cells17 or/and persistence of fetal cells in the maternal circulation (fetal microchimerism) after a first ongoing pregnancy18,19 may be the reason that
most women remain immunologically tolerant to the fetus in spite of production of antibodies and lymphocytes with reactivity toward fetal antigens. The maternal immune system therefore recognizes many paternal/fetal alloantigens during an ongoing pregnancy
and this very often induces permanent changes in immune reactivity to the fetus or
trophoblast that may reside in lymphocytes carrying immunologic memory (memory
T cells) in the peripheral blood, endometrium, or regional uterine lymph nodes. It is
also possible, although much less studied, that transcription of messenger RNA
(mRNA) and expression or production of proteins that are not related to the immune
function (eg, receptors for hormones in the uterus, production of coagulation factors
in the liver) can be permanently altered subsequent to the extensive physiologic changes
taking place during a prior ongoing pregnancy (a pregnancy passing GW 22).
Because of these considerations, in RPL case-control studies controls should be
matched to patients with RPL regarding a history of previous ongoing pregnancies
(see Table 2). The ideal control group for patients with RPL who had never had an
ongoing pregnancy would be women with repeated first trimester terminations due to
social reasons; however, because this group is fortunately small, an alternative suitable
control group would be women with no previous pregnancy. It may be argued that 1%
of nulligravida would later experience RPL, but this small error is insignificant compared
with the error associated with comparing nulliparous patients with RPL with multiparous
controls. Patients with secondary RPL who had previously had a birth should of course
be compared with controls with 1 previous live birth and no miscarriages.
Another factor that can confound case-control studies in RPL research and should
be adjusted for as much as possible is differences in hormones relating to
Research Methodology in Recurrent Pregnancy Loss
reproduction and pregnancy. Many factors relating to immune function (eg, cytokines)
and the coagulation system (eg, proteins C and S) are influenced by estrogen and progesterone levels.20 The level of expression of a series of cytokine mRNA in endometrial
cells increases markedly from the follicular to the late secretory phase, probably influenced by cyclic changes of estrogen and progesterone.21 It has been shown that lymphocytes that can induce immunologic tolerance (regulatory T cells) are attracted to
the feto-maternal interface by hCG produced by the trophoblast,22 which may have
profound importance for measurements of immune biomarkers in the uterus during
pregnancy. Because concentrations of hCG, estrogens, progesterone, cortisone,
and pregnancy-associated placental protein A (PAPP-A) change markedly according
to menstrual cycle phase or progressing gestation, the level of biomarkers affected by
hormones is dependent on phase of menstrual cycle or time of gestation. Therefore,
as a main rule, nongenetic biomarkers should be investigated in patients with RPL
and controls matched by menstrual cycle phase in nonpregnant women and length
of gestation during pregnancy (see Table 2).
A further problem arises when biomarkers in the blood or uterus, which are affected
by hormones, are investigated in patients with RPL just before or at the time of miscarriage and compared with similar measurements in controls with a healthy ongoing
pregnancy. Most of the pregnancy-related hormones, hCG, estrogen, and PAPP-A,
decrease in threatened miscarriage and finding differences in a specific biomarker between women with a miscarriage or a healthy pregnancy, respectively, may be
severely confounded by the fact that hormones in the former group are lower than
in the control group.
A last but important factor that may confound case-control studies in RPL research
is differences in the viability and inflammatory status of the uterine content before or at
the time of miscarriage in patients and at the time of induced abortion in controls. At
the time of embryonic death, the trophoblast will undergo necrosis and intrauterine
hemorrhage will often induce inflammation in the decidual tissue, which can be reflected in measurements of immunologic biomarkers in the blood or decidual/trophoblast tissue. In contrast, the same biomarkers in the blood of controls with an ongoing
normal pregnancy or in the blood or decidual/trophoblast tissue from controls with an
induced abortion on social indication will not be influenced by inflammation. Unfortunately, in many publications, levels of biomarkers associated with immune function or
apoptosis (programed cell death) in the blood or decidual/trophoblast tissue are
compared between women with a missed abortion and women with a normal ongoing
pregnancy or women undergoing induced abortion. In many of these publications,
finding differences in levels of such biomarkers are interpreted as proof that changes
in maternal immune reactions or apoptosis are causing miscarriage or RPL. To avoid
detecting biomarkers in patients with RPL that differ from those in controls merely due
to processes being a result of rather than a cause of miscarriage, measurements in peripheral blood should be undertaken in very early pregnancy (eg, GW 5) at a time when
the feto-placental unit is very tiny and not expected to affect systemic inflammatory
responses and before the confounding effect of declining hormones in patients take
place (see Table 2).23
Another approach to counteract the methodological problem associated with the
comparison of necrotic and vital tissue is to do karyotyping of embryos from missed
abortions in women with or without RPL. Biomarkers in the blood or decidual/trophoblast tissue can then be compared between patients with euploid male embryos (to
avoid erroneous karyotyping of maternal tissue) and patients with embryos with a
chromosome abnormality that definitively will cause early embryonic death. Levels
of biomarkers that are influenced by embryonic and trophoblast necrosis and
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inflammation may be equally affected in women with euploid and aneuploid miscarriages. Therefore, differences in expression of biomarkers between the women/embryos from the 2 groups can probably be attributed to factors that may have
caused euploid miscarriage. Examples of such studies that point to a causal role of
inflammatory cytokines in RPL is the study by Calleja-Agius and colleagues,24 finding
significantly higher plasma tumor necrosis factor-a, interferon-g, interleukin (IL)-6, and
IL-10 levels in women with euploid miscarriages than in healthy pregnancy, whereas
these cytokines were not increased in women with aneuploid miscarriages. Another
study similarly found increased numbers of activated leucocytes in RPL women
with a miscarriage with an euploid compared an aneuploid embryo.25
As illustrated previously, finding a suitable control group for measurement of nongenetically determined biomarkers is a difficult task. Adherence to the recommendations
given previously (see Table 2) may diminish the risk of conducting a case-control
study that is methodologically flawed but offers no guarantee. The factors that should
not differ between cases and controls in RPL research are the following:
Number of previous ongoing pregnancies
Levels of estrogen and progesterone in nonpregnant women
Levels of estrogen, progesterone, and hCG in pregnant women
Degree of viability of decidual or trophoblast tissue
I realize that very few case-control studies in RPL meet these criteria, especially the
criteria of similar hormonal levels. More research should be done regarding genetically
determined biomarkers because these are robust to the confounding effects discussed in this section. It is possible that some nongenetic biomarkers may also be
robust to the effects of the mentioned confounding factors (eg, reproductive hormones). However, only when it has been proven in separate studies that a specific factor (eg, hormone) is not affecting the biomarker under study, a confounding effect of
the factor can be ignored in subsequent case-control studies.
Lack of Protocol Data or a Priory Hypothesis
As a referee, I have often discovered that some research groups have published a
series of case-control studies in different articles often in different journals, each
case-control study dealing with only one specific biomarker, which was found to be
significantly increased in patients with RPL. When the articles are carefully read and
the data compared it seems that all the biomarkers have been investigated in the
same patient and control groups in the same period. In the articles, no information
was given about how many biomarkers were investigated in each study and what
was the a priori hypothesis. The suspicion is that in many of these studies, the investigators have tested a huge series of biomarkers using a multiplex testing panel that
can test for hundreds of (often genetic) biomarkers in 1 day and they report only
data of those biomarkers that (by chance) are found significantly increased in RPL. After this “fishing expedition,” the biomarkers being significantly associated with RPL
are published one by one in separate articles according to the “salami method”
without providing any information about how many biomarkers were investigated. In
this way, the investigators can expand their publication list in an easy way. This
“disguised multiple testing” is a maligned design, because the referees of the articles
have no chance to know that multiple testing was done and to ask the investigators to
do the appropriate statistical adjustment (see later in this article) and modify the conclusions. In the more benign cases, the investigators openly provide details of all
tested biomarkers/variables in tables and the referees can then ask for adjustment if
not already done.
Research Methodology in Recurrent Pregnancy Loss
This illustrates the problem that in many studies (especially case-control studies) dealing with RPL and other disorders, it is often unclear whether the result being reported as
the main finding really was part of the a priori hypothesis from the start or whether it was a
finding discovered during the conduct of the study: a post hoc finding (see Table 1).
As a preventive measure, high-ranking journals request the investigators to give
more details of the study protocols or the protocols should be available on an online
public registry (www.ClinicalTrials.Gov) before the beginning of the study. All journals
should, as a minimum, request the investigators in the “materials and methods” section to provide information from the study protocol about the a priori hypothesis, main
outcome measures, and sample size calculations, and to list all risk factors and biomarkers that were planned to test and actually tested.
Multiple Testing
Most case-control studies in RPL can be categorized as discovery studies in which
there is no prior hypothesis about which associations are probable and therefore a
series of biomarkers are investigated openly or disguised. Testing of multiple biomarkers is facilitated by the introduction of multiplex testing panels that can test hundreds of biomarkers at a time, thereby reducing the costs immensely. If, for example,
40 different biomarkers are tested in patients and controls and a P value for significance of less than .05 was chosen, it is expected that 2 (40 0.05 5 2) biomarkers
will be significantly increased or decreased in patients merely by chance. If no a priori
hypothesis about which biomarker was the primary focus of the study was made (discovery study) the P values for all tested biomarkers should be subject to the Bonferroni
adjustment by multiplying the P value with the number of comparisons made. If 1 or
2 biomarkers are still significantly associated with RPL after this adjustment, the association must be confirmed in at least 1 independent study (replication study) with the a
priori hypothesis that the variables are associated with RPL.
Interpretation
Causality can rarely, if ever, be stated after finding a potential risk factor statistically
significantly associated with a disease. According to Bradford-Hill criteria,26 there
are several demands for stating causality, the most important being the following:
The criterion of temporality: that the risk factor occurs before the occurrence of
the disease.
The criterion of a biologic gradient: there should be a positive correlation between the severity of a putative risk factor and the severity of the disorder.
In studies of RPL, the first criterion can be documented only in prospective studies
finding that the presence of a potential risk factor increases the risk of a new miscarriage compared with its absence. In RPL, the other criterion can be documented if
there is a correlation between the severity of a potential risk factor, for example, concentration of APL antibody, and the severity of RPL 5 number of miscarriages in the
patients. Findings in some previously quoted studies may indeed be interpreted as evidence against the investigated variables being causative for RPL because no biologic
gradient was discovered.7,8
COHORT STUDIES
As stated in the previous section: to document that an exposure found to be associated with RPL in a case-control study is indeed a causal factor for RPL, a prospective
study is needed.
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A prospective study is normally designed as a cohort study. A group of individuals
positive and another group of individuals negative for the exposure/potential risk factors for the disease (outcome) are identified. These 2 groups are now called cohorts
and they are observed during a defined time period in which the occurrence of the
outcome under study is monitored in the cohorts.
Concurrent Versus Nonconcurrernt Cohorts
In concurrent cohort studies, individuals assigned to the 2 cohorts are followed
prospectively, whereas in nonconcurrent (or retrospective) cohort studies, the assignment to the cohorts is done on the basis of the detection of an exposure at a time in the
past when the outcome under study had not yet happened. If the disease under study
is RPL, such a concurrent cohort study could ideally assign 20-year-old women who
had not yet been pregnant and who have been tested for relevant biomarkers into a
hereditary thrombophilia positive and negative cohort. These 2 cohorts are then followed until the women had aged 45 years and the occurrence of RPL in the 2 cohorts
is registered and compared between the cohorts. Adjustment for other risk factors for
RPL, such as age at the first pregnancy attempt, body mass index (BMI), and so forth,
should be undertaken in a multivariate analysis. It is clear that such a cohort study will
probably never be undertaken; because of the low frequency of RPL, tens of thousands of women must be included and followed for 25 years: nobody would have
the resources for that. Instead cohort studies focusing on pregnancy outcome after
a diagnosis of RPL will be a easier task to perform. Still, concurrent cohort studies
can take many years and therefore almost all cohort studies of patients with RPL
have been nonconcurrent. To give an example, my group investigated hereditary
thrombophilia factors (factor II and factor V Leiden mutations) in the patients referred
to the RPL clinic in Denmark between 1986 and 2008, in 62% of the cases using DNA,
which was stored but not tested for the thrombophilia-associated mutations before
after the outcome of the first pregnancy after referral had been registered.27 In most
cases, the patients and their doctors were therefore unaware of the exposure status
at the time of the first pregnancy after referral and none of the patients received anticoagulation treatment. In a good nonconcurrent cohort study, information about both
exposure and outcome status should not be available at the time the cohorts are
formed. The patients were thus in a nonconcurrent (retrospective) cohort study
assigned to a hereditary thrombophilia positive and negative cohort, and outcome
of the first pregnancy after referral to the clinic was “outcome.” In a logistic regression
analysis, adjusting for the impact of number of previous pregnancy losses, maternal
age, and smoking, it was found that the presence of the hereditary thrombophilia factors significantly decreased the OR for birth in the first subsequent pregnancy (OR 5
0.48, P 5 .05) compared with their absence. Thus, a much easier approach than doing
a large concurrent cohort study can provide results documenting the importance of
potential causal factors in RPL.
Nonrandom Misclassification
Cohort studies are prone to methodological errors, which are important to recognize
when conducting or assessing them. Nonrandom misclassification is a significant
threat to the validity of cohort studies; however, unlike case-control studies in which
the patients or controls are the main source of the erroneous information leading to
misclassification, in cohort studies it is the researchers who are responsible. In occupational medicine, workers are exposed to substances thought to increase the risk for
some disease. Because of that knowledge, these workers are often monitored more
closely than nonexposed workers and symptoms of disease (outcome) may be
Research Methodology in Recurrent Pregnancy Loss
registered more often in the exposed than in the nonexposed cohort. Biased intensity
of monitoring is also a problem in reproductive medicine research. In a cohort study of
women with obesity (the exposure) or no obesity, to investigate whether obesity
increases the risk of miscarriage, many obese women will have polycystic ovary syndrome (PCOS) and anovulation and therefore undergo assisted reproductive technology (ART) treatment, whereas most nonobese women will be able to conceive without
the need of ART. In ART cycles, a b-hCG test is normally done 14 days after ovulation
or embryo transfer, and all biochemical pregnancies will be detected, whereas among
non-ART patients, they will often remain undetected. Therefore such a cohort study
may show that obese women have an increased risk of pregnancy loss but this may
be a result of nonrandom misclassification of the outcome.
In RPL cohort studies, misclassification is also a significant problem. The prognosis
after a diagnosis of RPL is heavily disputed: various prospective studies have
reported the chance of live birth in the first pregnancy after referral in patients with
3 miscarriages to be between 63% and 87%, with 4 miscarriages between
44% and 73%, and with 5 miscarriages between 25% and 52%, respectively.11 These
very different estimates are frustrating: for a patient with RPL, it is of utmost importance to know whether her chance for live birth is 44% or 73%. This variation
may be caused by random misclassification within individual studies. Data from
2 placebo-controlled trials of intravenous immunoglobulin (IvIg) conducted in Sweden28 and Denmark,29 respectively, may clarify the issue. Patients with 3 or more miscarriages who met the inclusion criteria for participation in the trials were encouraged
to conceive and call the clinics as soon as they got pregnant. When the Swedish trial
(cohort 1) was concluded after 4 years, 50.6% of the patients were classified as not
having achieved pregnancy, only 3.4% had pre-embryonic losses, and 10.1% had
embryonic losses (Fig. 1). When the Danish trial (cohort 2) was concluded after
6 years, only 14.7% did not report pregnancy, 22.4% had pre-embryonic losses,
and 27.9% had embryonic losses. When live birth rates in cohorts 1 and 2 are calculated with the number of recognized pregnancies in the denominator, they become
72.7% and 44.8%, respectively (P<.005). The most striking difference between the
2 cohorts is the very much higher frequency of nonconception in cohort 1 than in
cohort 2. This may be because of the simple fact that the Danish patients were told
that they could not be included in the trial if they contacted the clinic more than
60
50
40
Not pregnant
Pre-embryonic losses
Embryonic losses
Live births
% 30
20
10
0
Cohort 1
N = 89
Cohort 2
N = 68
Fig. 1. Classification of pregnancy outcome in 4 categories of patients with RPL eligible for
participation in a Swedish (cohort 1) and a Danish (cohort 2) placebo-controlled trial of IvIg.
In each cohort, patients receiving IvIg and placebo are combined.
31
32
Christiansen
5 days after the missed menstrual period, whereas in the Swedish trial, patients were
included only when fetal heart action could be demonstrated in GW 6 to 7. In cohort 2,
every conception was probably registered, whereas in cohort 1, many pre-embryonic
losses may have been misclassified as nonconception. Another published cohort of
patients with RPL that estimated the chance of live birth in the first subsequent pregnancy, also found that 30% of the patients reported no further pregnancies after
referral to the clinic or were lost to follow-up.30 This is again a much higher frequency
that the 14.7% in the Danish cohort. As in the Swedish cohort, this difference is probably caused by incomplete follow-up resulting in misclassification of preclinical pregnancy losses as nonconception. When results from different cohort studies are
compared, this misclassification becomes nonrandom (see Table 1).
Cohorts Estimating Live Births Per Time Unit
The aforementioned examples illustrate the unreliability of studies of RPL cohorts
based on the patients’ self-reporting of outcome of the first subsequent pregnancy.
My group has therefore proposed a more robust method of estimating the prognosis
for the patients. We obtained information about subsequent live birth from the national
birth registry (which registers 100% of all births in Denmark) for all patients with RPL
referred to our clinic from 1986 to 2008. We could then calculate age-specific and prior
number of miscarriages–specific proportions of patients who had achieved a live birth
within 5 and 15 years after the first consultation (66.7% and 71.1%, respectively).11
Such an estimate with the rate of live birth in the numerator and the observation
time in the denominator is a robust and clinical relevant way to estimate the prognosis,
and it is not sensitive to the intensity of monitoring as in the previously discussed
methods. However, it can, of course, be used only in countries with a complete and
valid national birth registration system. Our estimates of the long-term live birth rates
in subsets of patients with RPL, most of whom had attempted pregnancy several
times after referral, are generally lower than those reported in the first pregnancy in
a frequently quoted cohort,30 and because our cohort is not sensitive to misclassification, the other cohort probably provides too optimistic rates.
TREATMENT TRIALS
In a time of embracement of evidence-based medicine, all treatments, new as well
as established, should undergo testing in clinical trials. With regard to RPL, clinical
treatment trials compare miscarriage rates in patients with RPL given one specific
treatment in the present pregnancy compared with outcome in a control group not
receiving the treatment.
Historical Controls
In some treatment trials, pregnancy outcome in a group of patients treated in the present was compared with outcome in nontreated controls from the past, so-called historical controls.
In a small study of PGS in the treatment of RPL in women aged 35 years,31 the live
birth rate after PGS was for each patient compared with the expected rate in women
with similar age and number of miscarriages calculated from a historical cohort.30 The
investigators found that the live birth rate after PGS was higher than the expected rate
using the data from the historical cohort. Comparing outcome in contemporary RPL
patient groups with historical control groups carries a substantial risk of producing unreliable results (see Table 1). It is extremely difficult to be sure that a group of patients
with RPL identified in the past is comparable with a present group, as ascertainment of
Research Methodology in Recurrent Pregnancy Loss
patients, screening methods, and pregnancy-monitoring procedures have changed
substantially with time.
A variant of the use of historical controls is the use of the treated patients as their
own controls. In RPL research, the live birth rate in patients with RPL before a specific
intervention is compared with the birth rate after the intervention. The use of this
method is still seen in publications especially concerning surgical treatment of RPL,
but also regarding other treatment modalities, such as metformin.32 Although using
the patients as their own controls at a first glance would appear ideal, this method
is severely flawed due to the phenomenon regression to the mean.33 The population
of patients with RPL may comprise the following:
A subset of women who have experienced the miscarriages merely because of
chance (repeated embryonic aneuploidies) with a low intrinsic risk of miscarriage
in each pregnancy but the women have been sampled asymmetrically from a
binominal distribution.
A subset of women with maternal risk factors with a higher intrinsic risk of
miscarriage.
In the former subset, on any subsequent measure (new pregnancy) the mean risk of
miscarriage will be closer to the (low) mean of the original population in spite of no intervention due to regression to the mean. If they are selected to a treatment trial, the
chance of success in the next pregnancy will be excellent in spite of no intervention.
In a trial of cerclage, the posttreatment birth rate was statistically significantly higher
than before cerclage and it was concluded that cerclage increases the live birth rate.
However, using this method, all types of interventions can be proved to be efficient
in the treatment of RPL, even placebo.34 In an RCT of infusion of allogeneic lymphocytes
versus placebo in RPL, the patients who received placebo had a live birth rate of 12.5%
before they entered the trial and subsequently 47.7% gave birth after placebo infusions.
By comparing birth rates before and after placebo by c2 test, the statistics claim that
placebo is highly efficient in treating RPL. This apparent, but false, improvement of
outcome can be completely attributed to the effect of regression to the mean.
Randomized Controlled Trials
Proper evaluation of treatments in RPL can be done only in RCTs. In RCTs, patients
are prospectively allocated to treatment or no-treatment or placebo by some randomization procedure that cannot be influenced by the researcher. This will increase the
chance that confounding variables, which can influence the prognosis, are equally
distributed in the groups.
Blinding
In the ideal RCT, allocation to active treatment or a placebo that cannot be distinguished from each other is undertaken according to a randomization list so that the
trial is blinded (masked) for both the researchers and patients, a so-called doubleblind design. The effects of blinding in RCTs are as follows:
Blinding of the doctors will ensure the same monitoring and concomitant therapy
in both groups
Blinding of the patients will provide them with the full placebo effect that due to
neuroendocrine pathways may exhibit a positive effect on pregnancy outcome in
RPL35
Blinding of the patients will diminish the dropout rate and associated poor registration of subsequent outcome in those allocated to the expected less-efficient
treatment
33
34
Christiansen
Several RCTs in the RPL area are unfortunately not blinded. None of the trials testing
the effect of heparin plus low-dose aspirin in patients with RPL with or without APL has
compared this intervention against a placebo for heparin but only against low-dose
aspirin alone or a peroral placebo for aspirin.36–38 This is probably due to the reluctance to use a placebo drug for daily subcutaneous injections during the whole period
of pregnancy. Although the outcome in RPL, a new miscarriage, can be determined by
objective methods that are not impacted by blinding/nonblinding, nonblinding can
negatively or positively influence outcome (see Table 1) in the groups receiving
nontreatment or expected less-efficient treatment compared with the expected
more-efficient treatment (tablets vs injections plus tablets).
Although a double-blinded randomized placebo-controlled trial is the best design to
obtain valid data concerning treatment effect, this method does not guarantee that the
results are trustworthy, as other circumstances can confound or weaken the results.
Confounding in RCTs
Most RCTs in RPL have included a small number of patients and this increases the risk
that a confounding variable, such as number of prior miscarriages and age, by chance
is unevenly distributed between the 2 allocation groups. In a small RCT, it is not sufficient to show that the mean number of previous miscarriages or age is not statistically significantly different in the 2 allocation groups; these variables can still
significantly confound the results. The best way to counteract uneven distribution of
prognostic variables in RCTs is by doing block-randomization, whereby separate allocation of patients is done according to groups with comparable number of miscarriages and age.
Inclusion after GW 6
In numerous RCTs, patients with RPL have been allocated and included in the trial only
when an ultrasonographic examination has demonstrated a viable intrauterine pregnancy in GW 6 to 7.28,38,39 This design can unfortunately substantially diminish any effect of the active intervention (see Table 1). Twenty-two percent of closely monitored
patients with RPL have pre-embryonic losses (see Fig. 1), which comprise almost half
of all their pregnancy losses.29 When treatment in RCTs starts only after the demonstration of fetal heart action, almost half of the risk period for miscarriage has thus
passed and the spontaneous prognosis at that time is good.40 Therefore, very large
numbers of participants are needed to show any treatment effect. Furthermore,
when treatment is started only in GW 6 to 7, the pregnancy has been exposed to
the full harmful effect of thrombophilic or immunologic factors for 2 to 3 weeks before
initiation of the potential beneficial therapy. The trophoblast or fetus, although viable at
that time, may have suffered irreversible damage that cannot be counteracted by initiating active therapy.
Premature discontinuation of an RCT
In many RCTs, at least 1 interim analysis is performed during the conduct of the trial
and it is prematurely stopped if the results at this analysis show that a statistically significant effect of the intervention could not be obtained even if the trial was continued
until the originally planned number of participants was reached. Many RCTs in the area
of RPL have been stopped prematurely after performance of an interim analysis,28,41,42 and this poses a substantial problem in interpreting the results, especially
when they are included in systematic reviews and meta-analyses. There is a great risk
that the difference between the outcome in the intervention and nonintervention/placebo groups at the stopping point after the interim analysis due to a random fluctuation is smaller than if the trial had been continued to the planned number of
Research Methodology in Recurrent Pregnancy Loss
participants; if the difference had been larger the trial had been allowed to continue.
RCTs stopped after interim analyses will therefore be expected to report intervention
effects that are smaller than the true effects (see Table 1) and, if included in systematic
reviews, their scientific quality should accordingly be down-graded.
Inclusion of several outcomes from the same patient
In case series and RCTs in RPL research, several pregnancy outcomes from the same
patients are sometimes included.43,44 This is a methodological flaw, as the outcomes
of pregnancies in individual patients with RPL due to the importance of maternal risk
factors (eg, age, number of prior losses) are linked variables. The commonly used statistical methods, such as c2 test and Fisher test, require that the tested variables are
independent and cannot be used. Therefore, only one pregnancy outcome from each
patient should be included in trials testing interventions, whether randomized or not.
Systematic Reviews
A systematic review is a review that uses systematic and explicit methods to critically
appraise a research topic; statistical methods such as meta-analyses may be used to
analyze and summarize the results of the included studies. Both case-control studies
and RCTs can be subject to such reviews and their results are considered the highest
level of evidence. In RPL research, systematic reviews have in particular focused
on intervention/treatment studies. The pooled OR calculated from the combination
of results in the meta-analysis is considered a good measure for the overall effect of
the intervention/treatment under study. However, because most treatments exhibit
different effects in different subsets of patients (eg, men and women or patients
with severe vs less severe disease), an important use of meta-analyses is to identify
subgroups of patients who have the largest benefit of treatment.45 I focus my discussion regarding systematic reviews in RPL on those dealing with immunotherapy with
IvIg, because these reviews have included the largest numbers of studies and patients
and the discussion illustrates the pitfalls and methodological flaws that characterize
systematic reviews in the area of RPL treatment. Four different systematic reviews
have been published concerning IvIg treatment in RPL,4,42,46,47 which have provided
very different results and conclusions. This variability is in my view caused by either
(1) a failure to recognize the need of doing separate analysis in relevant subgroups
of patients or (2) by unfounded exclusions of RCTs in the systematic reviews. A
Cochrane review4 did not find any difference in live birth rate between IvIg and placebo
in all included patients with RPL but made no distinction between patients with primary and secondary RPL, which would be relevant, as 2 published trials had found
the IvIg efficient exclusively in the latter group.29,48 In contrast, another systematic review based on almost the same patients recognized the relevance of doing this subgroup analysis and found the live birth rate significantly higher in IvIg-treated than in
placebo-treated patients with secondary RPL.46
The 2 most recent systematic reviews on IvIg in RPL included only patients with “unexplained” RPL, which meant that trials that had included patients with RPL positive
for APL according to the assays used in the individual clinics and according to the
local cutoff values were excluded.42,47 The investigators considered that 2 RCTs
included APL-positive patients and all 92 patients in these RCTs were completely
excluded from the systematic reviews comprising 25.3% of all 364 patients with
RPL participating in RCTs of IvIg. Exclusion of this substantial proportion of all randomized patients with RPL appears to be an enormous waste of valid information.
In one of the excluded RCTs, none of the patients in fact had APL and in the other
almost all patients who tested APL-positive had very low titers.49 Only 3% would be
35
36
Christiansen
considered APL-positive according to the current criteria.50 On the other hand, an RCT
that was not excluded did in fact include APL-positive patients51 and several of the
other RCTs did not report details of APL assays or cutoff levels. Because both
excluded RCTs had found a substantial effect of IvIg in patients with secondary
RPL, doing the meta-analyses without these resulted in the conclusion in both systematic reviews that there is no benefit of IvIg either in primary or secondary RPL.42,47 As
stated by my group and others, we find the methodology of these systematic reviews
questionable and without the exclusions it can be proved that IvIg is indeed efficient in
secondary RPL.49,52 As previously mentioned, it is legal and desirable to do metaanalyses in subgroups of patients to identify subgroups that benefit best from treatment, and such a subgroup could be patients with RPL without APL. However, a
systematic review excluding these patients should of course exclude only those
patients who are positive for APL and not complete RCTs with only a tiny minority
of participants being APL-positive. Furthermore, in most published relevant RCTs,
insufficient information is given about the APL assays and cutoff values, which may
vary substantially between the trials. To carry out a meta-analysis of therapies in
APL-negative patients with RPL based on good research methodology, it is therefore
necessary to collect data on APL levels for each included patient. In most cases, these
data on individual patients can be obtained only by contacting the investigators of the
RCTs. If such a collection of raw data is not done, the resulting systematic review and
meta-analysis will produce biased results.
This discussion illustrates that even conclusions from systematic reviews should be
evaluated critically and a systematic review is not per se the highest level of evidence.
If they are not conducted according to rigorous and systematic rules, they will end up
being no more evidence-based than the narrative reviews of the old days (see
Table 1).
SUMMARY
Most causes of RPL are poorly elucidated and may have a more multifactorial etiology
than infertility and in many instances the cause-effect relationship is unclear. Furthermore, the RPL population is much smaller that the infertile population, thereby making
it difficult to conduct studies with adequate statistical power.
These problems render research in RPL inherently difficult and only methodologically high-quality studies are expected to produce useful results. Unfortunately,
such high-quality research studies are rare in the area of RPL.
All types of studies in RPL research are characterized by methodological pitfalls,
which are often not recognized by the researchers or readers. Failure to recognize
these can completely invalidate studies in the area. It is hoped that this review, by
setting focus on the problem, can help improve studies in the area of RPL in the future.
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39
Th e Evo l vin g R o le o f G en et ic s i n
R e p ro d u c t i v e M e d i c i n e
Paul R. Brezina,
MD, MBA
a,b,c,
*, William G. Kearns,
PhD
d,e
KEYWORDS
Genetics Reproductive Preimplantation genetic screening
Preimplantation genetic diagnosis Preimplantation Chorionic villus sampling
Amniocentesis Cell-free DNA
KEY POINTS
Genetics is increasingly being applied to reproductive medicine for both diagnosis and
treatment.
Preconception genetic testing, including testing for carrier states of conditions such as
cystic fibrosis and hemoglobinopathies, will be increasingly used. There is an increasing
trend to de-emphasize race to determine the appropriate testing.
Antenatal genetic testing includes time-tested diagnostic evaluations such as chorionic
villus sampling and amniocentesis. In addition, newer minimally invasive testing modalities
are currently being developed and applied. The application of these tests is likely to increase in the future.
Preimplantation genetic testing, including testing for specific genetic diseases and aneuploidy, is the practice of analyzing a biopsied sample of an egg or embryo obtained
through in vitro fertilization. The ever improving accuracy and growing applications associated with this technology will likely lead to increased utilization.
Continued
Pertinent Disclosures and Conflicts of Interest: None.
Sources of Funding: None.
Contributors: P.R. Brezina primarily searched the literature. P.R. Brezina wrote the first draft of the
article; W.G. Kearns edited the article and M.A. Kutteh advised on the content of the article, assisted
in the literature search, and contributed to the writing of the article. P.R. Brezina is guarantor.
a
Reproductive Endocrinology and Infertility, Fertility Associates of Memphis, 80 Humphreys
Center, Suite 307, Memphis, TN 38120, USA; b Department of Obstetrics and Gynecology,
Vanderbilt University Medical Center, B-1100 Medical Center North, Nashville, TN 37232,
USA; c Department of Surgery, MS133, Room B3019, St. Jude Children’s Research Hospital,
262 Danny Thomas Place, Memphis, TN 38105-3678, USA; d Department of Gynecology and
Obstetrics, Johns Hopkins Medical Institutions, Phipps 264, 600 North Wolfe Street, Baltimore,
MD 21287, USA; e Preimplantation Genetics, The Center for Preimplantation Genetics, LabCorp, 15001 Shady Grove Road, Suite 200, Rockville, MD 20850, USA
* Corresponding author. Reproductive Endocrinology and Infertility, Fertility Associates of
Memphis, 80 Humphreys Center, Suite 307, Memphis, TN 38120, USA.
E-mail address: pbrezina@fertilitymemphis.com
Obstet Gynecol Clin N Am 41 (2014) 41–55
http://dx.doi.org/10.1016/j.ogc.2013.10.006
obgyn.theclinics.com
0889-8545/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
42
Brezina & Kearns
Continued
Genetic analysis following fetal demise is now capable of evaluating the genetic karyotype
of products of conception without growth in culture, through microarray technology. In
addition, certain microarray evaluations are capable of ruling out maternal cell contamination. These advances may improve the diagnosis and future treatment of women suffering
from failed pregnancy.
It is incumbent on clinicians, however, to ensure that these interventions are used in a
responsible, equitable, and ethical manner.
INTRODUCTION
At its core, reproductive medicine attempts to explain how human life is created and
how it develops throughout pregnancy. Based on this understanding, therapies are
developed and used to maximize outcomes. Specifically, increased pregnancy rates,
decreased incidence of obstetric complications and miscarriage, and the avoidance
of fetuses affected by birth defects or other deficiencies are the stated goal of
much of the current research in reproductive medicine. The role of genetic testing
to guide medical decision making in this regard is sizable and will likely continue to
grow in the future.
Genetic evaluations within reproductive medicine may be subdivided into 4 main
categories:
1. Preconception genetic testing: The genetic evaluation of prospective parents
before pregnancy
2. Antenatal genetic testing: The genetic evaluation of women who are currently pregnant to determine the genetic makeup of the developing fetus
3. Preimplantation genetic testing: The genetic evaluation of an embryo, before uterine transfer, via an embryo biopsy during an in vitro fertilization (IVF) procedure
4. Genetic analysis following fetal demise: The genetic evaluation of the products of
conception following a failed pregnancy
This article outlines each of these broad categories and describes the current
appropriate applications of these technologies.
PRECONCEPTION GENETIC TESTING
Preconception genetic testing is the genetic evaluation of prospective parents before
pregnancy (Box 1). Many individuals have a specific family history of certain genetic
disorders, but many may also be at risk for unknown genetic diseases. Preconception
genetic testing can be based on a couple’s ethnicity or the medical history of a genetic
Box 1
Preconception genetic testing
Many individuals may be unknown carriers of certain genetic diseases
Preconception testing for a variety of genetic diseases is increasingly recommended in
phenotypically normal individuals
Technological advances have improved the accuracy and have decreased the cost of such
testing
Race is increasingly de-emphasized to determine appropriate testing panels
Genetics and Reproductive Medicine
disease segregating in their families. Most genetic diseases identified because of
ethnicity are autosomal recessive disorders (AR), and require 2 mutations to have
the disease. For a fetus to be affected with an AR disorder, each parent must
pass along a mutation and, therefore, the fetal risk is 25%. One example of an AR disorder is cystic fibrosis (CF). In fact the carrier rate for CF among all individuals in the
United States is 1 in 37, but may be as high as 1 in 27 in certain ethnic groups.1
Genetic diseases segregating in a patient’s family can be autosomal dominant (AD),
AR, or X-linked (XL). For AD disorders, if the fetus has the mutation the baby will have
the disease. An example of an AD disorder is Huntington disease. XL disorders exist
on the X chromosome, and can be XL dominant or XL recessive. In simplistic terms,
most XL disorders are caused by unaffected carrier mothers passing along their
mutant X-chromosome to their affected sons. An example of an XL disorder is
fragile X.
Various modalities and technologies are used for preconception genetic testing,
and these test for the most common, though not necessarily all, mutations associated
with the genetic disease. Most testing technologies include direct mutation analysis by
genotyping, duplication/deletion analysis, and DNA sequencing, and can use classic
linkage analysis.
Preconception genetic testing for couples considering pregnancy specifically to
determine the carrier status for certain genetic AR disorders has been available for
some time.2 The list of recommended AR inherited disorders to evaluate in the context
of preconception evaluation is limited and is primarily based on the recommendations
of 2 societies.3,4 In addition, these societies often differ in exactly which tests are
recommended.
Common conditions currently tested in a preconception genetic evaluation based
on ethnicity include hemoglobinopathies (sickle cell trait, C trait, thalassemia trait, hemoglobin E), CF, Tay-Sachs disease, Canavan disease, familial dysautonomia, mucolipidosis IV, Niemann-Pick disease type A, Fanconi anemia group C, Bloom syndrome,
Gaucher disease, and spinal muscular atrophy.
In the past, most preconception genetic testing was tailored to patients according
to their ethnic background, as the carrier rate for specific disorders is known to differ
among various ethnic groups. As the population of pan-ethnic societies, such as the
United States, continues to become increasingly interracial, such targeted testing is
becoming increasingly problematic.3,4 A recent bulletin by the American Congress
of Obstetrics and Gynecology (ACOG) recently noted when evaluating this subject
that “it is becoming increasingly difficult to assign a single ethnicity to individuals.”3,4
Consequently, many experts now recommend offering universal carrier genetic testing
for many of these AR disorders within the context of preconception counseling to all
patients, regardless of their ethnic background.
When a positive result is obtained for a genetic disorder, the specifics of this result
and its clinical risk must be explained clearly to the patient either by their clinician or a
genetic counselor. In addition, patients should be counseled on available strategies to
minimize the risk of having an affected child, including preimplantation genetic diagnosis within the context of an IVF cycle. Referral to a reproductive endocrinologist
or geneticist familiar with these technologies may be advised.
ANTENATAL GENETIC TESTING
A central focus of obstetric care for many years has been to identify fetal disorders
during pregnancy. In the age of elective terminations following the Roe v. Wade United
Sates Supreme Court decision (410 U.S. 113; 1973), information regarding the status
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of the developing fetus has been used to guide medical decisions. In general, the
baseline incidence of some type of birth defect is approximately 3%.5 For many of
these defects, detailed ultrasonography and other methods are used to identify specific anatomic anomalies. However, in most instances these anomalies are associated
with a euploid (normal) genetic complement (either 46,XX or 46,XY). Although there
may also be specific genetic abnormalities associated with this myriad of birth defects
in euploid fetuses, genetic evaluation is currently not the modality used to identify such
problems. Therefore, the remainder of the discussion in this article focuses on the
genetic evaluations used to identify aneuploid (abnormal) genetic complements in
the developing fetus during pregnancy.
The Basics of Aneuploidy
Chromosomal aneuploidy, a condition in which either too many or too few chromosomes are present on any 1 of the 23 chromosome pairs, is a common occurrence
in human reproduction (Box 2). During the process, ovulation and fertilization human
oocytes (eggs) and sperm undergo a series of organized genetic separation events
known as meiosis. A simplified view of one of these events is outlined in Fig. 1. In
this scheme, a diploid (2 copies of a chromosome) is divided into 2; 1 represents an
ovulated egg and the other a discarded polar body. This haploid (having one copy
of each chromosome) egg then is fertilized by another haploid sperm, producing a
diploid embryo having 2 copies of each chromosome, one from each parent. In reality,
however, this is a very simplified and incomplete summary of this process. Maternal
meiosis in fact includes 2 phases of meiosis.
This process of meiosis is complex. If there is an uneven split of the chromosome
pairs during meiosis, as is shown in Fig. 2, the resulting egg either has 2 or no copies
of the chromosome. Following fertilization with sperm, this may result in either an extra
copy of a chromosome (trisomy) or only 1 copy, not 2 copies, of a chromosome
(monosomy). There are 23 chromosome pairs, and a splitting error on any 1 of these
chromosomes results in a chromosomal complement that is unbalanced and generally
not compatible with life. In fact, the only aneuploidy errors that can be compatible with
a live birth are errors in the number of sex chromosomes (eg, 45X, 47XXY, 47XYY) and
trisomy in chromosomes 13, 18, or 21. Of these trisomies, chromosome 21 (Down syndrome) is generally associated with fetal survival past 1 year of age, and is associated
with a host of developmental and health problems.
The focus of fetal genetic testing has traditionally focused on identifying trisomies in
13, 18, or 21 or X-chromosome monosomy, because these errors are the only problems that could be associated with a live birth. Aneuploidy errors on other chromosomes, while common, generally result in a failed pregnancy early in the first
trimester before traditional testing (such as sampling of chorionic villi or amniocentesis) can practically be performed. However, technologies are currently available
Box 2
Antenatal genetic testing
Aneuploidy is common in human embryos
Modalities for testing the genetic status of the human fetus in utero have existed for some
time, and include chorionic villus sampling and amniocentesis
Evaluation of maternal cell-free DNA is a minimally invasive testing modality that offers the
ability to identify aneuploidy in many cases. The application of this test is likely to increase in
the future
Genetics and Reproductive Medicine
Fig. 1. Normal chromosomal division. This scheme depicts a normal meiotic division of one
chromosome in which a diploid chromosome divides into haploid copies. One of these
haploid copies joins with a haploid sperm, resulting in a diploid embryo.
that permit a more complete and, in some cases, less invasive fetal genetic evaluation.
The following summarizes some of these interventions.
Chorionic Villus Sampling and Amniocentesis
Chorionic villus sampling (CVS) and amniocentesis are technologies that have been
used for decades to determine whether aneuploidy or structural chromosome aberrations are present in the developing fetus. Often, these interventions are used after
Fig. 2. Aneuploidy: meiotic nondisjunction. This scheme depicts the mechanism of meiotic
nondisjunction whereby a diploid chromosome fails to divide into 2 haploid copies. After
joining with a haploid sperm, this results in an embryo that has either 3 chromosomal copies
(trisomy) or 1 chromosomal copy (monosomy).
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there is some abnormality detected on ultrasonography or certain types of blood tests
(hat screen for maternal proteins) commonly performed to determine the risk of aneuploidy in early pregnancy. In addition, women of advanced maternal age (>35 years)
are often offered either CVS or amniocentesis. Both CVS and amniocentesis work
by surgically obtaining and genetically evaluating fetal cells. In CVS, these cells are obtained by sampling chorionic villi via ultrasound-guided needle biopsy between 10 and
14 weeks of gestation.6 Amniocentesis is performed by needle aspiration of amniotic
fluid around 15 weeks of gestation.6 At present, the samples obtained by either CVS or
amniocentesis may be evaluated to generate a fetal karyotype or other targeted
single-gene genetic testing as dictated by the clinical context.
However, CVS and amniocentesis have certain risks. First, the procedure of invasive
sampling used with both these approaches is associated with pregnancy loss. The
rate of pregnancy loss is estimated to be less than 1%, but is certainly not 0%.6 In
addition, there is some level of maternal physical discomfort and stress associated
with the performance of these procedures. Furthermore, CVS may provide spurious
results in patients with a condition known as confined placental mosaicism, a condition whereby the placenta possesses a mixture of aneuploid and euploid cells while
the fetus is euploid.
Cell-Free Fetal DNA Evaluation
It has been documented that nucleated cells derived from the fetal-placental unit can
be detected circulating in maternal blood at a level of 1 to 6 cells per milliliter of
maternal blood.7,8 More commonly observed in the maternal blood circulation are
cellular fragments of DNA, generally thought to be placental in origin. These placentally derived DNA fragments actually comprise approximately 3% to 6% of all circulating cell-free DNA in maternal plasma.5,9,10 These fragments may be detected very
early in pregnancy, but are not reliably present until later in the first trimester.7,8
In 2007, Down syndrome (trisomy 21) was detected by genetic evaluation of these
DNA fragments isolated from maternal blood.11 Since this landmark case, the utilization of cell-free fetal DNA evaluation has become increasingly common. At present
there are commercially available platforms that evaluate trisomies for chromosomes
13, 18, and 21 using this technique. However, these testing modalities are still considered a screen, and a diagnostic follow-up by CVS or amniocentesis is recommended.
Unlike CVS or amniocentesis, cell-free fetal DNA evaluation is noninvasive and is not
associated with any rate of pregnancy loss resulting from the performance of the
procedure. In addition, the test may be performed very early in pregnancy at approximately 10 weeks’ gestation, well before when CVS or amniocentesis is possible. As
this technology evolves and supportive data accumulate, an increased diagnostic
role for this technology may be appropriate.
PREIMPLANTATION GENETIC TESTING
An IVF cycle consists of administering injectable gonadotropins to women and
inducing controlled ovarian hyperstimulation whereby more than the usual number
of ovarian follicles are recruited and matured.12,13 The oocytes within these follicles
are then surgically harvested and inseminated with sperm. Typically resultant embryos
are then grown in vitro until either 3 or 5 days of development, at which time the 1 or
2 best embryos are placed into the uterus and the remaining embryos are cryopreserved. It is possible to biopsy a cell(s) from developing embryos before embryo
transfer, and to perform various genetic analyses that determine which embryos
would be optimal for either embryo transfer or cryopreservation. Therefore, the
Genetics and Reproductive Medicine
purpose of preimplantation genetic testing is to improve the likelihood of carrying a
pregnancy to term and giving birth to a healthy baby.
When first introduced around 1990, preimplantation genetic testing was used exclusively to determine whether embryos harbored a specific genetic mutation that was
known to exist from parental DNA analysis.14–16 This practice of evaluating embryos
for a known parental genetic defect is known as preimplantation genetic diagnosis
(PGD). As aneuploidy is the most significant reason for pregnancy failure, the technology of evaluating biopsied cells from embryos was then used to determine the ploidy
status of embryos before uterine transfer.17,18 This evaluation of embryonic cells
for aneuploidy from healthy parents, rather than a single genetic defect, is termed preimplantation genetic screening (PGS). PGD or PGS may be helpful to those who have
experienced problems with infertility, recurrent pregnancy loss (miscarriages), or unsuccessful IVF cycles. PGD may also be useful to couples who are at risk for passing
an inherited genetic condition on to their children (Box 3).
Preimplantation Genetic Diagnosis
As already discussed, PGD is the practice of evaluating embryos for a known parental
genetic defect. The utilization of this technology is now widely accepted as appropriate in couples harboring a known genetic abnormality.13 The chief uses of PGD
are outlined here.
Single-gene disorders
PGD for single-gene mutations diagnoses specific genetic mutations that are documented in the parents and segregating within their extended family. This goal is accomplished using polymerase chain reaction (PCR) to amplify the DNA of the chromosome
where the gene of interest resides.19 DNA sequencing then identifies the specific gene
Box 3
Preimplantation genetic testing (PGT)
PGT is achieved by obtaining a cellular biopsy from a developing human oocyte or embryo
obtained via an in vitro fertilization cycle, evaluating the genetic composition of this
sample, and using information gained from this process to determine optimal embryos for
subsequent uterine transfer.
PGT is performed by:
Obtaining cell(s) from either a developing embryo or oocyte
Genetic analysis of cells obtained at biopsy
PGT is subdivided into 2 broad categories
Preimplantation genetic diagnosis (PGD)
-
The purpose of PGD is to prevent the birth of affected children from parents with a
known genetic abnormality
-
PGD is widely acknowledged as acceptable for routine clinical application
Preimplantation genetic screening (PGS)
-
Attempts to identify aneuploidy in embryos to improve pregnancy success in certain
patient populations
-
Parents with no identified genetic defect or disease
-
PGS remains controversial for routine application
The results obtained by PGT may not always reflect the fetus’ genetic composition.
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mutation, and linkage analysis identifies surrounding markers used to determine
recombination and whether the DNA of the sperm and oocyte is amplified.20,21
Structural chromosome aberrations
In couples with recurrent pregnancy loss (RPL) and/or a documented balanced reciprocal/Robertsonian translocation (Fig. 3) or chromosomal inversion in one or both parents, PGD coupled with IVF has been shown to have some benefit in improving
pregnancy and live birth rates.22–24 Fluorescence in situ hybridization (FISH) has traditionally been used to identify the presence of translocation imbalances in PGD translocation cases. FISH identifies chromosomal balances or imbalances, but is unable to
rule out the presence of a balanced translocation chromosome. However over recent
years microarrays have been increasingly utilized. Microarrays are able to simultaneously identify genetic imbalances caused by the parental translocation or inversion
chromosome, and evaluate all 23 pairs of chromosomes from a single cell or cells. As
with FISH, microarrays can only identify genetic balances or imbalances, and cannot
differentiate the presence of a translocation chromosome from its normal
counterpart.23,25
Because of the complexities of PGD, all patients must be adequately counseled on
the risks and limitations of PGD, preferably with the aid of a specialized physician,
geneticist, or genetic counselor. Furthermore, antenatal genetic testing is still recommended in all patients undergoing PGS.13
Preimplantation Genetic Screening
PGS determines whether aneuploidy exists for any of the 23 pairs of chromosomes.
The transfer of euploid embryos seems to play a significant role in implantation and
fetal development. Determining which embryos are best has been a subject of
much debate since the advent of IVF technology in the late 1970s. Traditionally the
use of morphology (the visual appearance of embryos) has been the principal modality
of choosing optimal embryos for uterine transfer.26 However, the implantation rate per
transferred embryo in most clinics rarely exceeds 40%.27 Therefore, many investigators have for some time been searching to establish other diagnostic methods that are
Fig. 3. Balanced parental translocations. This scheme depicts the mechanism by which parents
who harbor a balanced chromosomal translocation may have offspring with unbalanced
translocation errors. Of note, parents harboring balanced chromosomal translocations may
also have offspring with different chromosomal combinations that may be phenotypically
or genetically normal.
Genetics and Reproductive Medicine
capable of determining embryo quality more accurately than morphology alone. PGS
improves the implantation rate and delivery rate for RPL patients and, possibly, other
clinical indications.
PGS, unlike PGD, has been and continues to be a controversial technology.
Recent studies indicate that approximately more than 70% of all first-trimester miscarriages are the result of chromosomal aneuploidy.13 Because so many early miscarriages are due to aneuploidy, PGS seems to be a reasonable intervention to
improve the efficiency with which euploid (chromosomally normal) embryos are
selected for uterine transfer in IVF cycles. Classic studies have reported that firsttrimester miscarriages resulting from aneuploidy are disproportionately concentrated
on select chromosomes.28,29 These data are based on karyotype analysis of failed
pregnancies that developed far enough to have tissue available for genetic
analysis.28,29 Consequently, clinics performing PGS in the early days of the technology focused on detecting aneuploidy on only select chromosomes using FISH, which
typically evaluates between 5 and 14 chromosome pairs rather than all 23 chromosome pairs.30,31 Traditionally, the PGS biopsy was exclusively performed at approximately 3 days of embryonic development following fertilization.30,31 Unfortunately,
this approach failed to lead to improvements in clinical pregnancy rates, and this
lack of efficacy was widely referenced following a landmark article by Mastenbroek
and colleagues32 in the New England Journal of Medicine. Subsequently, similar
articles cast further doubt on the benefits of PGS, and position statements from
major medical societies formally discouraged its use.16,33,34
Further research, however, elucidated several biological limitations that could
explain the prior shortcomings of clinically applied PGS. First, studies have repeatedly
documented that embryos at day 3 of development have high levels of mosaicism.35,36 A photograph of an embryo undergoing a day-3 biopsy is shown in
Fig. 4. Mosaicism is a condition whereby a single developing embryo comprises
more than 1 distinct genetic cell line. In other words, mosaic embryos may have
euploid (normal) and aneuploid (abnormal) cell lines within a single embryo. Studies
evaluating this phenomenon have concluded that as many as 50% of all embryos
may be mosaic at day 3 of development.35,36 Consequently, a biopsy performed at
day 3 of development may produce a result that is not representative of the entire
embryo.13 It is clear that embryos developmentally change during differentiation to
the blastocyst stage of development. Data have shown that mosaicism is greatly
reduced in blastocysts, to approximately 5%.13,37
Another limitation of traditionally performed PGS was the use of FISH for determination of chromosomal aneuploidies. FISH typically evaluates between 5 and 14 rather
than all 23 chromosome pairs.38 Recent studies have indicated that embryonic
Fig. 4. Cleavage-stage embryo. These photographs show an embryo at the cleavage stage.
On the right is a photograph of a cleavage-stage biopsy.
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aneuploidy occurs in clinically significant amounts in all 23 chromosome pairs.39
Therefore, FISH is incapable of diagnosing many of the chromosomal abnormalities
commonly found in developing embryos.
Realization of these 2 principal limitations have led many genetic laboratories to offer
PGS using technologies evaluating the chromosomal status of all 23 chromosome pairs
on cells obtained from differentiating blastocysts, typically reached by day 5 or day 6 of
embryo development. A photograph of an embryo undergoing a day-5 biopsy is shown
in Fig. 5. The clinical pregnancy rates using this approach have been reported to be
markedly superior to the traditional approach of performing PGS.40,41 For example, a
recent study evaluating more than 4500 embryos using determination of 23 chromosome pairs found clinical pregnancy rates in women suffering from RPL to be significantly improved in comparison with similar studies using FISH PGS.40 In addition,
pregnancy rates were further improved when 23-chromosome-pair evaluation PGS
was performed on blastocyst stage embryos (day 5/6 of development), compared
with when the biopsy was performed on embryos at day 3 of development.30,40,42
Similar results have been reported consistently by many clinics in the United States
and around the world.30,42,43 This trend has led to a renewed interest in PGS, although
it still remains to be determined whether PGS is an efficacious technology and which
patient populations are best served by PGS.
Evaluation technologies using all 23 chromosome pairs are complex and differ in
their experimental approach. The 2 most common technologies are microarrays and
real-time PCR.13 Both of these technologies rely on obtaining embryonic DNA, amplifying this DNA, and evaluating the amplified product using microarrays or real-time
PCR. This amplification process is a potential source of error, as failure to amplify
the entire embryonic DNA genome could produce a false result. In addition, all amplification protocols must be performed under sterile conditions so as to avoid any exogenous contamination.
There are 2 types of microarrays, single-nucleotide polymorphism (SNP) and
comparative genomic hybridization (CGH). SNP arrays directly evaluate ploidy by genotyping alleles on a dense chip of approximately 300,000 genetic markers.13 CGH arrays, by contrast, evaluate far fewer genetic markers and determine ploidy by
comparing the clinical DNA sample with male and female reference DNA samples.13
Each of these microarray platforms have advantages and disadvantages. SNP arrays
can identify loss of heterozygosity, consanguinity, and uniparental disomy whereas
CGH arrays cannot, because of their ratio labeling protocol.
Significant advantages of CGH arrays are that that they may be performed in
12 hours and provide the IVF clinic the opportunity to transfer the embryos on day
6 of embryo development, potentially eliminate the need for an embryo freeze and a
frozen embryo transfer, and can determine large clinically significant deletions or duplications. Real-time PCR is a molecular technique that determines the presence or
Fig. 5. Blastocyst-stage embryo. These photographs show an embryo at the blastocyst stage.
The leftmost photo shows the herniation of trophectoderm (TE) cells after the application of
a laser to breach the zona pellucida. The next 2 photographs show the process of obtaining
a sheet of TE cells that will be analyzed for preimplantation genetic screening.
Genetics and Reproductive Medicine
absence of 3 to 5 chromosomal loci on the test sample DNA. It then quantitatively
compares the chromosome copy number with a reference DNA sample. Real-time
PCR can reliably determine aneuploidy in approximately 6 hours and can also provide
IVF clinics the ability to transfer embryos on day 6 of development. One disadvantage
of real-time PCR is the inability to determine structural chromosome aberrations.
Evidence for the Clinical Application of PGS
Studies from centers using PGS on day-5 and day-6 blastocysts show promising results, with transferred embryos generating pregnancy rates greater than 72%.30,40,42
However, a central criticism of the widespread use of PGS is a lack of randomized
controlled trials that conclusively show the procedure to be beneficial. While some
prospective trials currently do exist that support the application of PGS to improve
pregnancy outcome, further studies are required before PGS will be more broadly
accepted.13,43,44
Despite the lack of support from professional societies and the lack of large, randomized controlled trials definitively demonstrating the benefits of the technology,
PGS comprises the major part of all preimplantation genetic testing internationally,
and is being increasingly used.45 However, the patient population for which PGS
may be appropriate is unclear at present.13 Many PGS clinics have traditionally recommended PGS for couples with risk factors believed to be associated with embryonic
aneuploidy such as unexplained RPL, severe male factor, and advanced maternal
age. However, in recent years many clinics have liberally expanded the use of PGS
to many women without such risk factors. In fact, some clinics broadly recommend
PGS to virtually all IVF patients as a strategy to improve pregnancy rates in all couples
battling infertility. The debate surrounding the appropriate patient populations for PGS
is currently in flux, and will likely be a source of debate for years to come.
Limitations of PGS
Despite the positive data emerging within the field of PGS, there are tangible technical
and biological limitations to the technology. The limitations of FISH PGS evaluation
and the use of biopsy taken from day-3 embryos are significant, as discussed earlier.
In addition, technical limitations surrounding the use of both SNP and CGH arrays and
real-time PCR may produce spurious results if not properly validated and experimentally performed.13
Perhaps the most significant source of error from PGS using 23-chromosome-pair
evaluation on cleavage stage (day 3) or blastocysts (day 5/6 of development) is the
presence of mosaicism within the developing embryo. Clearly it is not possible to
perform genetic testing on every cell of an embryo, as this is not compatible with
having a viable embryo available for uterine transfer. The best recommendation is to
perform 23-chromosome-pair PGS on blastocysts.
The aforementioned limitations of PGS demand that patients be adequately counseled on its risks and limitations, preferably with the aid of a specialized physician,
geneticist, or genetic counselor. Furthermore, antenatal genetic testing is still recommended in all patients undergoing PGS.13
New technologies associated with PGS are producing data suggesting that the
procedure could be a valuable adjunct to assisted reproductive technologies in
the future, to enhance pregnancy success in most patients. Defining the exact
benefit conferred by PGS and determining exactly which patient populations could
be best served by it, however, is currently controversial. In the near future, the field
should commission large and high-quality studies that will attempt to answer these
questions. Despite this lack of definitive data, however, PGS is increasingly being
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Box 4
Genetic analysis following fetal demise
Aneuploidy is extremely common in embryogenesis and is responsible for the lion’s share of
pregnancy losses in the early first trimester
Genetic analysis following fetal demise is now capable of evaluating the genetic karyotype
of products of conception without growth in culture through microarray technology
Certain microarray evaluations are capable of ruling out maternal cell contamination
These advances may improve diagnosis and future treatment of women suffering from failed
pregnancy
applied to patients with ever expanding clinical indications. Although there are few
large, randomized controlled studies defining the benefits of PGS, clinical data
emerging from many PGS laboratories around the world are encouraging. Therefore,
the judicious use of PGS seems reasonable at present, as the preponderance of
available current evidence suggests that some couples may derive benefit from
this technology. Only with time will the role of PGS be clearly defined.
GENETIC ANALYSIS FOLLOWING FETAL DEMISE
As discussed earlier in the PGS section, chromosomal aneuploidy is extremely
common in embryogenesis and is responsible for the lion’s share of pregnancy losses in the early first trimester. However, determining whether aneuploidy existed in
early first trimester losses has traditionally been difficult by routine karyotypic analysis, which requires the culture of cells followed by the generation of a G-banded
karyotype. Failed cultures attributable to the presence of toxic substances and/or
toxic cell products prohibit cell synchronization required for G-banding of metaphase chromosomes. Another important issue of routine karyotypic analysis of
products of conception (POC) tissue is maternal cell contamination. Because of
maternal cell contamination, with a 46,XX G-banded karyotype one cannot be
certain that the analyzed cells are fetal or maternal in origin, and are therefore of
little clinical value.
The introduction of SNP microarrays has dramatically changed the way firsttrimester pregnancy losses are being evaluated. Arrays are capable of amplifying
DNA samples from POC cells without requiring cell culture, thus permitting the
analysis of small initial samples without the requirement of metaphase chromosome
synchronization. Furthermore, SNP arrays determine genotypes, and if a maternal
DNA sample is run with the POC tissue, one can differentiate a fetal 46,XX karyotype
from a maternal 46,XX karyotype. Through these improvements, evaluation of firsttrimester POCs through SNP microarrays has become an important component of
the evaluation of RPL (Box 4).
SUMMARY
The past several decades have witnessed a dramatic increase in genetic diagnostics
and therapeutic interventions offered to patients. Reproductive medicine is no exception to this statement. As our understanding of genetics and its relation to disease expands, there surely will be an ever expanding role for genetics within reproductive
medicine. It is incumbent on clinicians, however, to ensure that these interventions
are used in a responsible, equitable, and ethical manner.
Genetics and Reproductive Medicine
ACKNOWLEDGMENTS
The authors thank Drs William Kutteh and Raymond Ke for their help in writing this
article. They also extend gratitude to Michael A. Kutteh for his assistance in the preparation and submission of this article. His contributions are greatly appreciated, as he
helped to facilitate the timely submission of this article.
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preimplantation embryos sexed by Y-specific DNA amplification. Nature 1990;
344:768–70.
53
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16. Practice Committee of Society for Assisted Reproductive Technology, Practice
Committee of American Society for Reproductive Medicine. Preimplantation genetic testing: a Practice Committee opinion. Fertil Steril 2008;90:S136–43.
17. Hassold T, Chen N, Funkhouser J, et al. A cytogenetic study of 1000 spontaneous
abortions. Ann Hum Genet 1980;44:151–78.
18. Menasha J, Levy B, Hirschhorn K, et al. Incidence and spectrum of chromosome
abnormalities in spontaneous abortions: new insights from a 12-year study. Genet
Med 2005;7:251–63.
19. Verlinsky Y, Cieslak J, Freidine M, et al. Pregnancies following preconception
diagnosis of common aneuploidies by fluorescent in-situ hybridization. Hum Reprod 1995;10:1923–7.
20. Laurie AD, Hill AM, Harraway JR, et al. Preimplantation genetic diagnosis for hemophilia A using indirect linkage analysis and direct genotyping approaches.
J Thromb Haemost 2010;8:783–9.
21. Cirulli ET, Goldstein DB. Uncovering the roles of rare variants in common disease
through whole genome sequencing. Nat Rev Genet 2010;11:415–25.
22. Kuliev A, Verlinsky Y. Current features of preimplantation genetic diagnosis. Reprod Biomed Online 2002;5(3):294–9.
23. Treff NR, Northrop LE, Kasabwala K, et al. Single nucleotide polymorphism
microarray-based concurrent screening of 24-chromosome aneuploidy and unbalanced translocations in preimplantation human embryos. Fertil Steril 2011;
95(5):1606–12.e2.
24. Otani T, Roche M, Mizuike M, et al. Preimplantation genetic diagnosis significantly
improves the pregnancy outcome of translocation carriers with a history of recurrent miscarriage and unsuccessful pregnancies. Reprod Biomed Online 2006;
13(6):869–74.
25. Du L, Brezina PR, Benner AT, et al. The rate of de novo and inherited aneuploidy
as determined by 23-chromosome single nucleotide polymorphism microarray
(SNP) in embryos generated from parents with known chromosomal translocations. Fertil Steril 2011;96(3):S221.
26. Brezina PR, Zhao Y. The ethical, legal, and social issues impacted by modern assisted reproductive technologies. Obstet Gynecol Int 2012;2012:686253.
27. Ajduk A, Zernicka-Goetz M. Advances in embryo selection methods. F1000 Biol
Rep 2012;4:11.
28. Monni G, Ibba RM, Zoppi MA. Prenatal genetic diagnosis through chorionic villus
sampling. In: Milunsky A, Milunsky JM, editors. Genetic disorders and the fetus.
6th edition. Oxford (United Kingdom): Wiley-Blackwell; 2010.
29. Kearns WG, Pen R, Graham J, et al. Preimplantation genetic diagnosis and
screening. Semin Reprod Med 2005;23(4):336–47.
30. Schoolcraft WB, Fragouli E, Stevens J, et al. Clinical application of comprehensive chromosomal screening at the blastocyst stage. Fertil Steril 2010;94:
1700–6.
31. Brezina PR, Kearns WG. Preimplantation genetic screening in the age of
23-chromosome evaluation; why FISH is no longer an acceptable technology.
J Fertiliz In Vitro 2011;1:e103.
32. Mastenbroek S, Twisk M, Echten-Arends J, et al. In vitro fertilization with preimplantation genetic screening. N Engl J Med 2007;357:9–17.
33. Checa MA, Alonso-Coello P, Solà I, et al. IVF/ICSI with or without preimplantation genetic screening for aneuploidy in couples without genetic disorders:
a systematic review and meta-analysis. J Assist Reprod Genet 2009;26:
273–83.
Genetics and Reproductive Medicine
34. Mastenbroek S, Twisk M, van der Veen F, et al. Preimplantation genetic screening:
a systematic review and meta-analysis of RCTs. Hum Reprod Update 2011;17:
454–66.
35. Harton GL, Magli MC, Lundin K, et al, European Society for Human Reproduction
and Embryology (ESHRE), PGD Consortium/Embryology Special Interest Group.
ESHRE PGD Consortium/Embryology Special Interest Group—best practice
guidelines for polar body and embryo biopsy for preimplantation genetic diagnosis/screening (PGD/PGS). Hum Reprod 2011;26:41–6.
36. Munné S, Weier HU, Grifo J, et al. Chromosome mosaicism in human embryos.
Biol Reprod 1994;51:373–9.
37. Brezina PR, Sun Y, Anchan RM, et al. Aneuploid embryos as determined by
23 single nucleotide polymorphism (SNP) microarray preimplantation genetic
screening (PGS) possess the potential to genetically normalize during early
development. Fertil Steril 2012;98(3):S108.
38. Harper JC, Sengupta SB. Preimplantation genetic diagnosis: state of the art
2011. Hum Genet 2012;131:175–86.
39. Brezina PR, Tobler K, Benner AT, et al. All 23 chromosomes have significant levels
of aneuploidy in recurrent pregnancy loss couples. Fertil Steril 2012;97(3):S7.
40. Brezina PR, Tobler K, Benner AT, et al. In vitro fertilization (IVF) cycles and
4,873 embryos using 23-chromosome single nucleotide polymorphism (SNP)
microarray preimplantation genetic screening (PGS). Fertil Steril 2012;97:S23–4.
41. Wells D, Alfarawati S, Fragouli E. Use of comprehensive chromosomal screening
for embryo assessment: microarrays and CGH. Mol Hum Reprod 2008;14:
703–10.
42. Forman EJ, Tao X, Ferry KM, et al. Single embryo transfer with comprehensive
chromosome screening results in improved ongoing pregnancy rates and
decreased miscarriage rates. Hum Reprod 2012;27:1217–22.
43. Scott RT Jr, Upham KM, Forman EJ, et al. Blastocyst biopsy with comprehensive
chromosome screening and fresh embryo transfer significantly increases in vitro
fertilization implantation and delivery rates: a randomized controlled trial. Fertil
Steril 2013. http://dx.doi.org/10.1016/j.fertnstert.2013.04.035.
44. Yang Z, Liu J, Collins GS, et al. Selection of single blastocysts for fresh transfer via
standard morphology assessment alone and with array CGH for good prognosis
IVF patients: results from a randomized pilot study. Mol Cytogenet 2012;5:24.
45. Harper JC, Wilton L, Traeger-Synodinos J, et al. The ESHRE PGD Consortium:
10 years of data collection. Hum Reprod Update 2012;18:234–47.
55
Uterine Factors
Carolyn R. Jaslow,
PhD
KEYWORDS
Recurrent miscarriage Uterus Septum Fibroids Uterine anomalies
Pregnancy loss Congenital Acquired
KEY POINTS
Uterine anomalies are one of the most common factors associated with recurrent pregnancy loss (RPL).
Congenital anomalies, such as bicornuate, unicornuate, didelphic, and septate uteri, most
likely result from HOX mutations in the developing Müllerian ducts.
Of the acquired uterine anomalies, adhesions are typically formed after endometrial
trauma, such as curettage, whereas fibroids and polyps are benign growths of the myometrium and endometrium, respectively.
Many studies have explored the effects of uterine anomalies with respect to reproductive
outcomes, but there are few randomized controlled trials, particularly for patients with
RPL, and treatment methods lack strong supporting evidence.
Nonetheless, metroplasty to correct a septate uterus and surgical removal of severe adhesions are recommended, and myomectomy of submucosal fibroids should be considered if no other causes have been identified.
INTRODUCTION
Recurrent pregnancy loss (RPL) is a frustrating disease that can cause considerable
emotional distress in couples, often leading to a variety of other illnesses, both mental
and physical.1,2 Most often, RPL is caused by genetic abnormalities in the embryo3;
nonetheless, chromosomal translocations, endocrine or metabolic disorders, autoimmune disorders, and anatomic anomalies of the uterus are considered the most likely
parental causes associated with RPL.4 Among the most prevalent of these parental
factors are uterine anomalies, which are reported to occur in 19% of women with at
least 2 consecutive miscarriages.5 These anomalies include intrauterine adhesions,
fibroids, and endometrial polyps that are acquired after birth, as well as congenital
defects that arise from alterations in embryonic development, such as arcuate, bicornuate, didelphic, septate, T-shaped and unicornuate anomalies.
Disclosure: Nothing to disclose.
Department of Biology, Rhodes College, 2000 North Parkway, Memphis, TN 38112, USA
E-mail address: cjaslow@rhodes.edu
Obstet Gynecol Clin N Am 41 (2014) 57–86
http://dx.doi.org/10.1016/j.ogc.2013.10.002
obgyn.theclinics.com
0889-8545/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
58
Jaslow
IMAGING TO DIAGNOSE UTERINE ANOMALIES
Diagnostic testing for RPL causes can be costly and time consuming, but testing for
anatomic abnormalities can bear the additional burden of subjecting a patient to an
invasive procedure. Methods to identify uterine anomalies have included pelvic examination and dilation and curettage (D&C), hysterosalpingography (HSG), laparoscopy,
laparotomy or other abdominal surgeries, two-dimensional or three-dimensional (3D)
transabdominal or transvaginal ultrasonography alone or with saline infusion (sonohysterography [SHG]), magnetic resonance imagining (MRI), and hysteroscopy. Differences in sensitivity and specificity among these procedures have undoubtedly
contributed to discrepancies in the literature regarding the prevalence and the reproductive consequences of uterine anomalies. Recent reviews identified 3D ultrasonography, SHG, hysteroscopy, and MRI as the most accurate procedures for diagnosis of
uterine anomalies.6–10 For detecting the separation of the uterine horns that distinguishes a bicornuate or didelphic uterus from a uterus with a partial or a complete
septum, respectively, an external assessment of the uterus is needed. Thus, laparoscopy or laparotomy must accompany hysteroscopy for accurate diagnosis of these
congenital anomalies.6,7 Although hysteroscopy has the advantage of providing a
direct view of the uterine cavity, and it can permit surgical correction of anomalies
at the time of the procedure,11 it is riskier and more invasive than the other imaging
methods with high accuracy. Techniques such as MRI and 3D SHG are useful because
they provide a recorded image of the anomaly, which can be saved and can allow subsequent measurements of the size and location of the anomaly.
NORMAL EMBRYOLOGY OF THE UTERUS
By the eighth week of gestation, the embryo has formed the paired Müllerian (paramesonephric) ducts that give rise to the oviducts, uterus, cervix, and the upper vagina.12
Development of a single uterus starts with fusion of the Müllerian ducts near their
caudal ends.12 A septum initially separates the 2 ductal lumina, but it is gradually
resorbed to produce a single uterine cavity.12 This process may be controlled by uterine expression of Bcl-2, a protein that regulates apoptosis.13 Case studies of women
with a septate uterus and duplication of the cervix and vagina indicate that fusion begins at the developing uterine isthmus and progresses cranially and caudally simultaneously, followed by bidirectional resorption of the septum.14 The unfused cranial
portions of the 2 Müllerian ducts form the paired oviducts.
Based on studies of mice and other vertebrates, the Müllerian ducts originate from
invagination of the coelomic epithelium lining the cranial end of the embryonic mesonephros.15 These invaginating cells give rise to both the epithelium and the surrounding mesenchyme of the ducts, which canalize as they elongate caudally to contact the
urogenital sinus.14–16 The sites of invagination become the ostia of the oviducts, and
the urogenital sinus becomes the lower vagina.17 In the absence of testicular hormones (eg, anti–Müllerian hormone, testosterone), differentiation of the Müllerian
ducts into the organs of the female reproductive tract involves reciprocal signaling
between the duct epithelium and mesenchyme. Initially, the mesenchyme induces
region-specific differentiation of the epithelium.18 The epithelium then releases
Wnt-7a signaling factors, which stimulate positional expression of a cluster of Hoxa
genes located along the cranial-caudal axis of the mesenchyme, leading to proper
morphogenesis of the oviducts, uterus, cervix, and upper vagina (Box 1).19–21 In the
uterus, the Müllerian duct epithelium forms the simple columnar epithelial lining and
glands of the endometrium, and the mesenchyme forms the endometrial stroma
and the myometrium.18,22
Uterine Factors
Box 1
Cranial-caudal expression of the HOXA genes along the Müllerian ducts directs the
development of the female reproductive organs
Oviduct - HOXA9
Uterus - HOXA10 and HOXA11
Cervix - HOXA11 and HOXA13
Upper vagina - HOXA13.
Adapted from Taylor HS, Vanden Heuvel GB, Igarashi P. A conserved Hox axis in the mouse and
human female reproductive system: late establishment and persistent adult expression of the
Hoxa cluster genes. Biol Reprod 1997;57:1341.
CONGENITAL UTERINE ANOMALIES
Classification and Embryology
Abnormalities in the formation, fusion, or differentiation of the Müllerian ducts, or in the
regression of the septum, produce congenital uterine anomalies. The most common of
these are the arcuate, bicornuate, didelphic, septate, T-shaped, and unicornuate
forms (Fig. 1) defined by the American Fertility Society (AFS), now known as the American Society for Reproductive Medicine.23 Agenetic defects may also occur, as can
severe uterine hypoplasia, such as that associated with Mayer-Rokitansky-KusterHauser syndrome,24 but these anomalies are usually associated with amenorrhea or
infertility, rather than RPL. Some studies have described other types of congenital
anomalies and proposed alternative classification systems,14,25 but the forms characterized by the AFS are the most prevalent, and their system is the most widely used.
Defects in formation of 1 Müllerian duct: unicornuate uterus
Agenesis or hypoplasia of 1 of the paired Müllerian ducts can result in a unicornuate
uterus arising from the contralateral duct.26 The term unicornuate implies that only 1
duct develops into a uterus; however, 74% of all unicornuate uteri have a rudimentary
horn, which may or may not have a cavity, and may or may not communicate with the
contralateral uterine cavity.27 One complication of a rudimentary horn with a cavity is
that it creates a site for an ectopic pregnancy, which can occur even in a noncommunicating rudimentary horn because of transperitoneal passage of sperm or fertilized
ova.28
Defects in fusion of the Müllerian ducts: didelphic uterus and bicornuate uterus
A didelphic uterus forms if the 2 Müllerian ducts fail to fuse and each gives rise to a
uterine horn with its own cervix (see Fig. 1).29 A bicornuate uterus develops if the 2
Müllerian ducts fuse at their caudal regions, but remain separated at their cranial regions.29 This situation creates 2 horns with connecting cavities and a common cervix
(see Fig. 1). If the indentation between the 2 unfused horns of a bicornuate uterus
extends to the cervix, the anomaly is a complete subtype.23 A partial subtype can
show a range of separation between the horns.30
Imaging techniques that show the V-shaped external contour of the fundus distinguish didelphic and bicornuate uteri from septate or arcuate anomalies. However,
septate and arcuate uteri may have a minor degree of external indentation, so various
quantitative criteria have been suggested to distinguish them from a partially bicornuate uterus. These criteria include the length or position of the indentation, or whether
the angle it makes is acute or obtuse.31–33
59
60
Jaslow
Fig. 1. Classification system of Müllerian duct anomalies. (From AFS. The American Fertility Society classifications of adnexal adhesions, distal tubal
occlusion, tubal occlusion secondary to tubal ligation, tubal pregnancies, Müllerian anomalies and intrauterine adhesions. Fertil Steril 1988;49:952;
with permission.)
Uterine Factors
Defects in regression of the septum: septate uterus and arcuate uterus
When the Müllerian ducts fuse completely and develop a normal external appearance,
but the tissue between the 2 ducts is not resorbed, or is resorbed only partway, this
creates a septate uterus (see Fig. 1).29 A uterine septum is complete if it extends
from the fundus through the cervix, or partial (subseptate) if it does not extend beyond
the internal cervical os and permits communication between the 2 areas of the uterine
cavity.34,35 Histologic sections of septa show areas of irregularly organized smooth
muscle, and also areas containing more connective tissue, particularly at the caudal
tip of the septum.32,36,37 Some aberrant vascular features have also been noted using
MRI or histology.30,37,38
In an arcuate uterus, the internal fundus forms a broad but shallow bulge into the
uterine cavity (see Fig. 1).32 Many studies rely on this description for diagnosis, but
others have proposed various criteria to quantify the projection.39–42 There is no generally accepted formula. Some investigators describe a slight indentation of the external
fundus and consider the arcuate uterus to be a mild form of a bicornuate uterus.34,43
However, most studies characterize the fundal contour as normal, convex, or slightly
flat,23,30 which indicates that fusion of the 2 Müllerian ducts was complete and that
the arcuate bulge is a small remnant of incomplete septal resorption. This explanation
for the embryonic origin of an arcuate uterus is supported by MRI and sonographic data
showing that the arcuate projection has muscular tissue like that in a partial septum.30 It
also has an unusual vascular pattern similar to the vascularization in a septum.30 Inclusion of the arcuate form with other congenital uterine anomalies is controversial
because some consider it a variation of normal uterine morphology, or at most, a minor
anomaly.23,30 Consequently, certain studies may include arcuate uteri in their reports of
congenital anomalies, whereas others do not.44–47
Defects in differentiation of the Müllerian ducts: diethylstilbestrol drug-related
uterus (T-shaped and hypoplastic)
Normally, the fused Müllerian ducts differentiate to form a uterus with a rounded
cavity, but in patients exposed to diethylstilbestrol (DES) in utero, the uterine body becomes deformed, and the cavity becomes T-shaped and reduced in size (see Fig. 1).48
CAUSE
Environmental Factors
Because congenital uterine anomalies are uncommon and are often asymptomatic in
the general population, identification of likely causes is challenging. A variety of environmental factors such as thalidomide, or exposure to infectious agents or ionizing radiation, have been suggested as possible teratogens,43 but there is little evidence
linking these environmental agents with the specific congenital uterine anomalies
observed in women with RPL. In contrast, the effect of estrogenic endocrine disruptors on the development of T-shaped uterine anomalies is well documented, particularly for DES, a synthetic estrogen that was prescribed to prevent miscarriage in
several million women from the 1940s until the 1970s.19,48 Prenatal exposure to estrogenic endocrine disruptors such as DES affects uterine morphology by triggering
changes in both the location and the amount of HOXA/Hoxa expression in the developing Müllerian duct.49–51 Specifically, Hoxa9 expression moves from the oviducts
into the uterus, and Hoxa10 and Hoxa11 are expressed in different locations in the
uterus, creating changes in the overall uterine form.51
There are no known environmental causes for congenital uterine anomalies other
than estrogenic endocrine disruptors such as DES.
61
62
Jaslow
Genetic Factors
Of 61 patients who had RPL and congenital uterine anomalies, only 1.9% had significant chromosomal rearrangements (eg, balanced translocations and mosaics).45 This
finding supports the assertion that most women with congenital uterine anomalies
have a normal 46 XX karyotype,43 and that any genetic basis for congenital uterine
anomalies lies with mutations at the molecular level rather than with gross chromosomal rearrangements. For example, different types of HOXA13 mutations cause
congenital uterine defects that are part of hand-foot-genital syndrome.52 More
recently, a woman with a didelphic uterus was found to have a novel mutation in a
HOXA10 gene,53 one of the HOXA genes responsible for normal uterine development
(see Box 1). Furthermore, this mutation was shown to cause a functional amino acid
substitution in the HOXA10 protein, which alters its ability to regulate other genes.53
Despite this discovery, it is not yet clear how the altered HOXA10 protein might lead
to a didelphic defect. Given the lack of direct connections between allelic sequence
changes and most types of congenital uterine anomalies, and because only about
10% of uterine anomalies can be attributed to inheritance among families,54 it seems
that congenital uterine anomalies are most likely caused by a mix of different genes
and epigenetic effects.55
Congenital uterine anomalies are caused by HOX gene mutations, although the
mechanism is most likely polygenic.
Gross chromosomal rearrangements are unlikely to produce the congenital uterine anomalies associated with RPL.
PREVALENCE
Considerable variation exists among studies reporting the prevalence of congenital
anomalies, in part because of a lack of consensus regarding the criteria used to define
anomalies, and in part because some of the imaging methods used for diagnosis have
low accuracy. Table 1A shows the results of a meta-analysis performed using only
data that were collected with imaging techniques defined as highly accurate by
Chan and colleagues6 and Saravelos and colleagues.7 Congenital uterine anomalies
(arcuate, bicornuate, didelphic, septate, T-shaped, and unicornuate types) were found
in 16.4% of women with RPL. When arcuate uteri were excluded because they may be
considered a normal form or a minor variant, this value decreased to about 8.4% (see
Table 1B). Even without arcuate forms, the 8.4% rate of uterine anomalies was 7 times
greater than the frequency of 1.2% among women in the general population, a rate
that is likely an overestimation because it includes women presenting with pelvic
pain and abnormal bleeding.7 A recent review reported that women who had a history
of miscarriage had significantly greater rates of congenital anomalies compared with
women in unselected populations.6
Table 2 lists the prevalence of specific types of congenital anomalies among
women with RPL compared with rates reported for the general population by systematic reviews.6,7 The data for women with RPL are derived from meta-analyses of
studies that used 3D ultrasonography, SHG, or hysteroscopy and laparoscopy for
diagnosis (Table 3). The T-shaped uterus is not included here because its prevalence
is linked to exposure to DES, which was discontinued after 1971. A septate uterus is
the most common type of congenital anomaly among patients with RPL (6.1%). For
bicornuate, septate, and unicornuate anomalies, the prevalence among patients
with RPL is at least twice that in the general population. The frequency of didelphic
uteri does not differ between groups, perhaps because the rates reported in the
Uterine Factors
Table 1
A
Study
Anomalies/
Patients
%
95% CI
13.6
(6.3–23.1)
Souza et al56
9/66
Weiss et al57
32/165
19.4 (13.7–25.8)
Bohlmann et al58
28/206
13.6
Ghi et al44
52/284
18.3 (14.0–23.0)
Valli et al42
112/344
32.6 (27.7–37.6)
Salim et al46
121/509
23.8 (20.2–27.6)
Jaslow & Kutteh45
All Studies
70/875
424/2449
8.0
(9.2–18.6)
(6.3–9.9)
16.4 (14.9–17.9)
B
Study
Anomalies/
Patients
Tulppala et al60
4/55
7.3
(1.6–15.9)
5/66
7.6
(2.2–15.4)
57
19/165
11.5
(7.0–16.9)
15/197
7.6
(4.3–11.8)
20/206
9.7
(6.0–14.2)
Stephenson
47
Bohlmann et al
Ghi et al
58
44
Valli et al
44/284
42
Salim et al
46
Jaslow & Kutteh
All Studies
95% CI
56
Souza et al
Weiss et al
%
45
15.5 (11.5–19.9)
33/344
9.6
(6.7–12.9)
35/509
6.9
(4.8–9.2)
61/875
7.0
(5.4–8.8)
236/2701
8.4
(7.4–9.5)
Prevalence of all congenital uterine anomalies with (A), and without (B) arcuate anomalies among
patients with RPL. Studies were included if they had subjects with 2 or more or 3 or more miscarriages,
reported the frequency for all types of congenital anomalies, and used 3D ultrasonography, SHG, or hysteroscopy and laparoscopy for diagnosis. Forest plots were generated with the MIX 2.0 Pro software for
meta-analysis in Excel, which used the Freeman-Tukey double arcsine transformation to calculate the
95% confidence intervals, weights, and the prevalence proportions for each study and for the summary
of all studies.59
63
64
Jaslow
Table 2
Prevalence of congenital uterine anomalies in women with RPL and women in the general
population
a
b
Anomaly
Prevalence in Patients
with RPL (%)
Prevalence in the General Population (%)6,7
Bicornuate
1.2a
0.3–0.4
Didelphic
0.2b
0.03–0.3
Septate
6.1a
2.0–2.3
Unicornuate
0.5a
0.03–0.1
Arcuate
4.6a
3.9–4.9
Prevalence of all studies from Table 3.
Prevalence from Jaslow and Kutteh.45
2 reviews of the general population vary by an order of magnitude. Arcuate uteri also
show no difference between women with RPL and those in the general population.
About 4% to 5% of women have an arcuate uterus, irrespective of whether they
have RPL; however, there is a considerable variation among studies reporting the
prevalence of an arcuate uterus in patients with RPL (see Table 3D). Most likely,
this variation reflects the difficulty of distinguishing an arcuate uterus from a normal
uterus if the arcuate projection is small, or from a subseptate (or possibly bicornuate)
uterus if the arcuate projection is large. It is also possible that the prevalence of
arcuate and didelphic uteri do not differ between women with early RPL and the general population because neither uterine anomaly represents a cause for early RPL.
Congenital anomalies, particularly septate uteri, are more prevalent in women
with RPL than in the general population.
CONGENITAL ANOMALIES AND FIRST-TRIMESTER PREGNANCY LOSS
Spontaneous miscarriage occurs in about 11% to 15% of clinical pregnancies among
women in the general population.62,63 This finding is comparable with the 13% to 15%
rate of first-trimester miscarriages reported by Chan and colleagues64 for control patients in their meta-analyses of congenital uterine anomalies and reproductive outcomes. In this study, patients with septate (including subseptate), bicornuate, and
unicornuate uterine anomalies had significantly greater risks of first-trimester miscarriage than did the controls. In contrast, arcuate and didelphic uteri did not increase the
first-trimester miscarriage risk, although arcuate anomalies did increase the risk of
miscarriage in the second trimester. Other studies have reported similar patterns in
which higher rates of first-trimester miscarriage occurred in women with septate, unicornuate, or bicornuate anomalies compared with those with arcuate, didelphic, or
normal uteri (Table 4).40,65–67 These results support the argument that arcuate and
didelphic uterine forms do not contribute to the likelihood of early RPL, but that
septate, unicornuate, and bicornuate anomalies may warrant further consideration
in patients presenting with at least 2 consecutive early losses.
One limitation of these studies is that they did not restrict their sample population to
patients with RPL. In the 1 study that included only women with 3 or more consecutive
losses,68 the frequency of first-trimester miscarriages in a subsequent pregnancy was
higher than among women in the general population, but the rates did not differ based
on the type of congenital anomaly (see Table 4). Because women with congenital
anomalies do not always experience diminished reproductive outcomes, it is reasonable that the miscarriage rate would be lower for the general population than for
Uterine Factors
Table 3
A
Study
Anomalies/
Patients
%
95% CI
Weiss et al57
3/165
1.8 (0.2–4.6)
Stephenson47
1/197
0.5 (0.4–2.2)
Bohlmann et al58
5/206
2.4 (0.7–5.1)
Ghi et al44
8/284
2.8 (1.2–5.1)
Salim et al46
6/509
1.2 (0.4–2.3)
Jaslow & Kutteh45
7/875
0.8 (0.3–1.5)
30/2236
1.2 (0.8–1.7)
All Studies
B
Study
Weiss et al57
Stephenson47
Anomalies/
Patients
13/165
8/197
%
95% CI
7.9 (4.2–12.5)
4.1
(1.7–7.3)
Bohlmann et al58
15/206
7.3 (4.1–11.3)
Ghi et al44
36/284
12.7 (9.0–16.8)
Salim et al46
27/509
5.3
(3.5–7.4)
Jaslow & Kutteh45
43/875
4.9
(3.6–6.5)
142/2236
6.1
(5.1–7.1)
All Studies
(continued on next page)
65
Jaslow
66
Table 3
(continued)
C
Study
Anomalies/
Patients
%
95% CI
Weiss et al57
1/165
0.6
(0.5–2.6)
Stephenson47
1/197
0.5
(0.4–2.2)
Bohlmann et al58
0/206
0
(0.0–1.4)
Ghi et al44
1/284
0.4
(0.3–1.5)
Salim et al46
2/509
0.4
(0.0–1.2)
Jaslow & Kutteh45
6/875
0.7
(0.2–1.4)
11/2236
0.5
(0.2–0.9)
%
95% CI
13/165
7.9
(4.2–12.5)
Bohlmann et al58
8/206
3.9
(1.6–7.0)
Ghi et al44
8/284
2.8
(1.2–5.1)
All Studies
D
Study
Weiss et al57
Salim et al46
Jaslow & Kutteh45
All Studies
Anomalies/
Patients
86/509
16.9 (13.8–20.3)
9/875
1.0
(0.5–1.8)
124/2039
4.6
(3.7–5.5)
Prevalence of bicornuate (A), septate (B), unicornuate (C), and arcuate (D) types of congenital uterine
anomalies, among studies of patients with RPL. Studies were included if they had subjects with 2 or
more or 3 or more miscarriages and used 3D ultrasonography, SHG, or hysteroscopy and laparoscopy
for diagnosis. Forest plots were generated with the MIX 2.0 Pro software for meta-analysis in Excel,
which used the Freeman-Tukey double arcsine transformation to calculate the 95% confidence intervals,
weights, and the prevalence proportions for each study with prevalence greater than 0% and for the
summary of all studies.59 The upper 95% CI was calculated as 1–0.051/n for investigations with prevalence
of 0%.61
Uterine Factors
Table 4
Frequency of pregnancies ending in first-trimester miscarriage among women with
congenital uterine anomalies in 2 different study populations
Anomaly
Rates for All Women (%)
Rates for Only Women with RPL (%)68
Bicornuate
38
64
72
Didelphic
1164
80
Septate
3464
73
Unicornuate
20–2426,64
60
Arcuate
15–20a
73
Abbreviation: RPL, Recurrent pregnancy loss, defined by Saravelos and colleagues68 as 3 consecutive miscarriages.
a
The rate of 15% excludes 1 study that had a miscarriage rate (34%) more than double that reported by the other 4 studies in the review (14%–16%).64
women with RPL. Further research is needed to confirm the pattern of the firsttrimester miscarriage rates among the different types of congenital defects in women
with RPL, particularly because the rates for the didelphic and unicornuate anomalies
were based on pregnancies for only 1 patient in each category.
The likelihood of first-trimester miscarriage is higher in women with septate, bicornuate, or unicornuate uterine anomalies than among women in the general
population, particularly if the women also have a history of RPL.
POSSIBLE MECHANISMS CAUSING MISCARRIAGE
First-trimester miscarriage is a risk for women with congenital uterine anomalies, but
little is known about the mechanisms responsible, which may be different from those
acting to cause miscarriage later during pregnancy. For example, 2 factors suggested
to cause reduced pregnancy outcomes in women with congenital uterine anomalies
are cervical incompetence and reduced muscle in the myometrium.26 However, these
are doubtful causes for early RPL because they would be more likely to cause problems when fetal size is greater during the latter part of a pregnancy. In 1 study of
women with a septate uterus, first-trimester miscarriage occurred more often among
embryos implanted on the septum than those implanted elsewhere on the uterine
walls.69 Histologic studies comparing the septum with the other uterine walls found
differences in the proportion of connective tissue relative to muscle, and in vascularization and endometrial structure, all of which could play a role in miscarriage.37,38,70
Altered uterine blood flow is another factor believed to cause pregnancy loss in
women with congenital uterine anomalies,34 and different types of studies provide
support for this hypothesis. Doppler ultrasonography showed different uterine blood
flow and perfusion in pregnant women who subsequently experienced firsttrimester miscarriages, and in those who had congenital uterine anomalies.71,72 Dye
tracings in the uterine vasculature showed that women with bifurcated uterine arteries
had experienced more miscarriages compared with women who had normal single arteries, although it was not stated whether these losses were early or late.73 Possibly,
the absence or modification of the uterine arteries in a unicornuate uterus or a uterus
with a fusion defect causes a change in blood flow, which leads to first-trimester pregnancy loss.74
More research is needed to identify how congenital uterine anomalies cause firsttrimester miscarriage, but alterations in vascularization and blood flow may be
factors.
67
68
Jaslow
TREATMENT OPTIONS
Metroplasty
Unicornuate uterus
Metroplasty is not recommended for a unicornuate uterus, although surgical removal
of an existing rudimentary horn is recommended to reduce dysmenorrhea and other
menstrual complications, and to avoid the risk of an ectopic pregnancy.29
Bicornuate uterus
Previously, surgical repair of a bicornuate uterus was recommended for women with
RPL, but only if other factors for miscarriage were ruled out.75–77 A transabdominal
metroplasty was traditionally used to effect uterine repair,76 but studies have reported
success performing this surgery laparoscopically.75 Because of the invasiveness of
this procedure and the paucity of clinical studies showing improved outcomes, surgical repair of a bicornuate uterus is seldom performed in the United States.
Didelphic uterus
Some investigators recommend treating a didelphic uterus the same way as a bicornuate uterus by performing metroplasty only in women with RPL for whom no other
cause can be identified.75,76 Others believe that surgical correction is unlikely to
improve reproductive outcome.29,78 It remains unclear whether surgical correction is
warranted in women with RPL who have a didelphic uterus.
Septate uterus
Although there are no randomized controlled trials,79 reviews have shown that hysteroscopic removal of a complete or partial uterine septum produces substantial reductions in miscarriage rates among women with RPL, as well as among women with RPL
and other obstetric complications.31,80,81 In most cases, these investigations report
pregnancy rates or rates of spontaneous abortions without clarification whether the
losses occurred in the first trimester or later. This situation makes it more difficult to
assess the benefit of septum resection specifically for patients with RPL in the first
trimester, although a single study82 did find that first-trimester miscarriage rates in
these patients dropped from 96% to 16% after hysteroscopic metroplasty of the
septum.
Arcuate uterus
The effect of an arcuate uterus on reproductive success is controversial, as is the
question of whether to recommend surgical removal. One review stated directly that
“women with such anomalies do not benefit from surgical intervention,”34 and others
have not recommended surgery because they do not believe that arcuate anomalies
affect reproductive outcome.77,83 Although some studies found that miscarriage rate
declined after arcuate metroplasty, none separated first-trimester losses from later
ones.39,84–86 Because women with an arcuate uterus have a higher frequency of
second-trimester miscarriages compared with women who have a normal uterus,40,64
arcuate metroplasty appears to have little advantage for a patient who is suffering from
first-trimester RPL.
Cervical Cerclage
Cerclage of the cervix has been reported to improve reproductive outcomes for patients with a range of congenital uterine anomalies,87 although randomized, controlled
studies are lacking.26 In most cases, cervical cerclage is noted as a solution for latetrimester losses and preterm births rather than for resolving first-trimester
miscarriages.
Uterine Factors
For women with early RPL who have congenital uterine anomalies, there is
an absence of randomized controlled trials comparing the effect of surgical
correction with expectant management; nonetheless, metroplasty is recommended for women who have a septate uterus, and it may be considered as
a last resort for women with a bicornuate uterus if no other causes have been
identified.
ACQUIRED UTERINE ANOMALIES
Acquired uterine anomalies associated with RPL include intrauterine adhesions,
fibroids, and endometrial polyps. These anomalies develop after puberty, often
because of some physical or hormonal stimulus. Acquired anomalies occur in about
12% of women with RPL, but this frequency ranges widely from 1% to 33%
(Table 5A). This variation is most likely the result of differences and ambiguity in
criteria for diagnosis, particularly for adhesions.
Adhesions
Characteristics and classification
Intrauterine adhesions connect opposing walls of the uterus. At one extreme, they are
sites where the uterine walls have fused, obliterating all or parts of the uterine cavity
and the normal functional and basal layers of the endometrium.94,95 For women
with RPL, adhesions more likely are bands of tissue extending from wall to wall (called
fibrosis by Yu and colleagues95). These adhesions may be thin strands of endometrial
tissue, fibromuscular connections covered with abnormal endometrium (these are the
most commonly observed), or bands of fibrous connective tissue with no endometrial
covering.95–97 In 1988, the AFS published a system that classified the type of adhesion
(filmy to dense), the extent of the cavity involved (from <one-third to >two-thirds), and
an assessment of the patient’s menstrual pattern (normal to amenorrheic).23 Others
have proposed different classifications, some of which include information about
the histology of the adhesions or the reproductive performance of the patient, but
none has been used consistently.97,98
Cause
Adhesions arise after destruction of the regenerating basal layer of the endometrium.99,100 In a study of 1856 cases of adhesions, more than 90% occurred in patients
who had experienced curettage during induced abortions or for complications after
birth or spontaneous abortions.99 Further evidence comes from prospective studies
that reported adhesions in 19% to 40% of patients examined hysteroscopically after
curettage.101,102 In addition to curettage, infection with genital tuberculosis can cause
adhesions, and uterine surgery or other traumas (eg, myomectomy) are possible
causes.99
Some predisposing factors for adhesions include infections and heredity, but the
foremost factor is pregnancy, probably because it makes the endometrium vulnerable
to physical trauma so that curettage more easily removes or damages the basal
layer.96,99 Another hypothesis is that the decrease in estrogen level with loss of the
placenta at birth or miscarriage plays a role, because estrogen stimulates regeneration
of the endometrial basal layer.95 Schenker and Margalioth99 noted that adhesions
were more likely to arise when curettage was performed between 2 and 4 weeks
post partum, possibly related to hormonal changes.100 Another key factor believed
to predispose women to develop adhesions is the retention of products of conception
in the uterus after pregnancy or during a missed abortion.99,100
69
Jaslow
70
Table 5
A
Study
Anomalies/
Patients
%
95% CI
Ventolini et al88
7/23
30.4 (13.0–51.0)
Dendrinos et al89
15/48
31.3 (18.8–45.2)
Tulppala et al60
7/55
12.7
(5.0–23.0)
Guimarães Filho et al90
19/58
32.8 (21.2–45.4)
Souza et al56
13/66
19.7 (10.9–30.3)
Cogendez et al91
18/82
22.0 (13.6–31.6)
Raziel et al92
27/106
25.5 (17.6–34.2)
Weiss et al57
Stephenson47
Bohlmann et al58
18/165
12/197
58/206
10.9 (6.6–16.2)
6.1
(3.1–9.9)
28.2 (22.2–34.5)
Coulam93
Valli et al42
Jaslow & Kutteh45
All Studies
2/214
0.9
(0.0–2.8)
30/344
8.7
(6.0–12.0)
113/875
12.9 (10.8–15.2)
339/2439
12.5 (11.2–13.8)
B
Study
Anomalies/
Patients
%
95% CI
Ventolini et al88
5/23
21.7
(6.9–41.2)
Dendrinos et al89
9/48
18.8
(8.8–31.2)
Tulppala et al60
5/55
9.1
(2.7–18.4)
Guimarães Filho et al90
Souza et al56
16/58
7/66
27.6 (16.8–39.9)
10.6
(4.1–19.3)
Cogendez et al91
Raziel et al92
Weiss et al57
10/82
25/106
11/165
12.2 (5.9–20.3)
23.6 (15.9–32.2)
6.7 (3.3–11.0)
Stephenson47
Bohlmann et al58
Coulam93
Valli et al42
11/197
26/206
1/214
15/344
5.6
12.6
0.5
4.4
(2.8–9.3)
(8.4–17.5)
(0.4–2.0)
(2.4–6.8)
17/453
36/875
194/2892
3.8
4.1
5.5
(2.2–5.7)
(2.9–5.5)
(4.7–6.4)
Li et al104
Jaslow & Kutteh45
All Studies
(continued on next page)
Uterine Factors
Table 5
(continued)
C
Study
Ventolini et al88
Dendrinos et al89
Tulppala et al60
Souza et al56
Cogendez et al91
Raziel et al92
Weiss et al57
Stephenson47
Bohlmann et al58
Coulam93
Ghi et al44
Valli et al42
Li et al104
Jaslow & Kutteh45
All Studies
Anomalies/
Patients
2/23
4/48
0/55
2/66
2/82
0/106
5/165
1/197
19/206
0/214
19/284
13/344
19/453
53/875
139/3118
%
95% CI
8.7 (0.2–24.5)
8.3 (1.9–18.1)
0 (0.0–5.3)
3.0 (0.0–8.9)
2.4 (0.0–7.2)
0 (0.0–2.8)
3.0 (0.9–6.3)
0.5 (0.4–2.2)
9.2 (5.6–13.6)
0 (0.0–1.4)
6.7 (4.0–9.9)
3.8 (2.0–6.1)
4.2 (2.5–6.3)
6.1 (4.6–7.7)
4.5 (3.7–5.4)
D
Study
Anomalies/
Patients
%
95% CI
Ventolini et al88
Dendrinos et al89
Tulppala et al60
Souza et al56
Cogendez et al91
Raziel et al92
Weiss et al57
Stephenson47
0/23
2/48
2/55
4/66
7/82
2/106
2/165
0/197
0
4.2
3.6
6.1
8.5
1.9
1.2
0
(0.0–12.2)
(0.1–12.1)
(0.1–10.6)
(1.3–13.4)
(3.3–15.7)
(0.0–5.6)
(0.0–3.6)
(0.0–1.5)
Bohlmann et al58
15/206
7.3
(4.1–11.3)
Coulam93
1/214
0.5
(0.4–2.0)
Ghi et al44
9/284
3.2
(1.4–5.6)
Valli et al42
2/344
0.6
(0.0–1.7)
27/875
3.1
(2.0–4.3)
73/2665
2.4
(1.8–3.1)
Jaslow & Kutteh45
All Studies
Prevalence of all acquired uterine anomalies (A), adhesions (B), fibroids (C), and polyps (D) among studies
of patients with RPL. Studies were included if they had subjects with 2 or more or 3 or more miscarriages,
reported the frequency of all types of acquired anomalies, and used 3D ultrasonography SHG, or hysteroscopy for diagnosis. Forest plots were generated with the MIX 2.0 Pro software for meta-analysis in Excel,
which used the Freeman-Tukey double arcsine transformation to calculate the 95% confidence intervals,
weights, and the prevalence proportions for each study with prevalence >0% and for the summary of all
studies.59 The upper 95% CI was calculated as 1–0.051/n for investigations with prevalence of 0%.61
71
72
Jaslow
Women with RPL may be predisposed to develop intrauterine adhesions if they undergo curettage after each of their multiple pregnancy losses. Not only is the frequency of adhesions higher in women with 2 or more postabortion curettages
compared with those with only 1 procedure, but the adhesions are more severe.101,103
Prevalence
A meta-analysis of studies that used SHG or hysteroscopy showed that adhesions
occurred in 5.5% of patients with RPL (see Table 5B). In contrast, adhesions were
detected in 1.5% to 3% of women who had a hysteroscopy before tubal sterilization,105 or before in vitro fertilization (IVF) for idiopathic or male factor infertility, or
for problems unrelated to uterine anomalies (eg, tubal factors).106,107
The prevalence of adhesions among the studies in Table 5B ranged widely, from
0.5% to 28%. Some of this variation may be attributed to differences in classification
and diagnosis. Of the 14 studies represented, only 5 describe the criteria used to report
adhesions. In 1982, Schenker and Margalioth99 suggested that the prevalence of adhesions reported by 90 studies varied because of different diagnostic criteria used by clinicians in various locations, as well as their awareness of the problem. These
investigators also noted that there might be regional differences in some of the causes
for adhesions, such as the frequency of elective abortions (particularly illegal abortions),
the techniques used for evacuation, and the prevalence of genital tuberculosis.99
First-trimester pregnancy loss
A 1982 review reported a miscarriage rate of 40% for 7 studies of women with adhesions, although the investigations were not restricted to patients with RPL.99 Miscarriage may occur because adhesions diminish the available uterine space and restrict
expansion99; however, these limitations may not be as important in the first trimester
as later in pregnancy. In a uterus with adhesions, the endometrium may be abnormal
or it may be replaced by fibrous connective tissue, and the myometrium may also have
a greater degree of fibrosis than the myometrium of a normal uterus.108,109 Uteri with
adhesions may also have diminished vascular density, which reduces blood flow
through the myometrium,110 although it is not clear if this occurs as a consequence
of fibrosis. Collectively, these factors reduce the amount of functional endometrium,
which may interfere with normal placental invasion and development.95,99,109
Treatment options
There are no studies that assess the success of expectant management compared
with adhesiolysis, other than a review from 1982,99 which reported a 40% miscarriage
rate for women without surgery and a 25% rate for women who had surgery. Reviews
with more recent data show miscarriage rates of about 15% to 16% after adhesiolysis.95,100 In 2 investigations, miscarriage rates after surgery were reported separately
for patients with infertility and for those with pregnancy loss (defined as pregnancy
wastage or 3 losses).97,111 Women with pregnancy loss had a miscarriage rate of
only 10% (10/103) after surgery, compared with a rate of 30% (24/79) for infertile
women, which suggests that adhesiolysis might be a more effective treatment for
women with RPL than for women with other reproductive problems.
The treatment of adhesions is surgical removal, but because uterine surgery is a
cause for adhesions in the first place, the techniques used should seek to prevent
recurrence of the adhesions and to facilitate endometrial regeneration.95 Recent thorough reviews summarize some of the advantages and disadvantages of these
methods, which include different instruments used to lyse adhesions, methods of
guidance, physical barriers to prevent contact between the walls after lysis, and hormone treatments to stimulate endometrial regeneration.94,95,100
Uterine Factors
Damage to the endometrium via curettage is the predominant cause of adhesions. This damage may increase the risk of adhesions for women with RPL if
their multiple pregnancy losses cause them to undergo repeated curettage.
The reported prevalence of adhesions is highly variable, possibly because of
differences in diagnosis or the causes among study groups.
Women with adhesions seem to have a high rate of miscarriages, but the
supporting evidence for this is limited.
Although there is a great need for randomized controlled studies of this issue,
surgical removal of adhesions should be recommended for women with RPL
who have no other known causes, with great precaution taken to prevent
recurrence.
Fibroids (Leiomyomata)
Characteristics and classification
Fibroids are benign smooth muscle tumors that originate in the myometrium and may
grow to invade other parts of the uterus. Several reviews (eg, Ciarmela and colleagues112
and Flake and colleagues113) have described a range of fibroid cellular and extracellular
properties, some of which are summarized in Box 2.
Fibroids are typically classified according to their anatomic position123:
Submucosal fibroids distort the uterine cavity and may be subdivided based on
whether they are pedunculated, have less than 50% intramural penetration, or
50% or more intramural penetration.
Box 2
Cellular and extracellular characteristics of fibroids compared with myometrial tissue, and
some examples of the functions or significance of these features
1. Fibroids contain abnormal myocytes and a large amount of aberrant extracellular matrix
(ECM)114,115
eg, the abnormal fibroid ECM, composed of fibroblasts, collagen, fibronectin, and
proteoglycans, is a source of signaling factors and mediators that communicate with
the smooth muscle cells of the fibroid to promote growth.116,117
2. Fibroids have different densities of receptors for estrogen, progesterone, and growth
factors113,118
eg, an altered ratio of alpha and beta estrogen receptors in fibroids compared with
myometrium may promote estrogen-stimulated fibroid growth.119
3. Fibroid cellular and extracellular proteins and enzymes are expressed in different quantities
and have different levels of activity
eg, reduced activity of 17b-hydroxysteroid dehydrogenase, which converts estradiol to
the less potent estrone,118 likely contributes to fibroid growth. Recently, proteomic
techniques have identified several other fibroid proteins and enzymes that have altered
expression compared with myometrium.120
4. Fibroids express different quantities of growth factors
eg, platelet-derived growth factor C (PDGFC) is one of the many growth factors that are
overexpressed and thus promote growth in fibroids.121
5. Fibroids may show degenerative changes
eg, degenerative features such as hyaline deposits, calcification, and hemorrhage may
appear in large fibroids, presumably because they have outgrown their blood supply.122
73
74
Jaslow
Intramural fibroids do not distort the uterine cavity and do not extend more than
halfway through the serosal surface of the uterus.
Subserosal fibroids extend 50% or more through the serosal surface and may be
pedunculated.
Cause and development
Risk factors linked with fibroids include nulliparity, early onset of menarche,
increased age, obesity, and African American ethnicity.113 In addition, about 50%
of surgically removed fibroids have gross chromosomal rearrangements, particularly a translocation between chromosomes 12 and 14 (t(12;14)(q14-15;q23–24)),
a deletion on chromosome 7 (del(7)(q22q32)), and various alterations on chromosome 6 (6p21)113,124 Some of these cytogenetic anomalies vary with fibroid location125 and size,126 and molecular analyses have found regulatory genes with the
potential to affect fibroid growth (eg, HMG) located in or near the regions of the
chromosomal abnormalities.113,124 Furthermore, fibroids can show epigenetic
markers that likely contributed to their development, such as altered DNA methylation in the promoter region of an estrogen receptor that increased expression of
the receptor.117,127
The development of fibroids includes the formation of an abnormal myometrial cell,
followed by proliferation of that cell into a benign tumor.128 It is established that proliferation of cells to form a fibroid is driven by exposure to estrogen and progesterone
and is regulated by several autocrine growth factors, other signaling molecules (eg, interleukins), and components of the extracellular matrix (see Box 2 and comprehensive
reviews113,117). On the other hand, the factors responsible for the transformation of a
normal cell to an abnormal one, possibly with some of the genetic or epigenetic anomalies listed earlier, are less clearly understood.
Some hypotheses for the initiation of a fibroid, summarized by Flake and colleagues,113 propose that individuals with higher levels of estrogen and progesterone,
or more receptors for those hormones, have a greater risk for somatic mutations in
their myometrium because estrogen and progesterone increase the rate of mitosis.
It has also been suggested that the appearance of a cell with a tendency to proliferate
may be a response to hypoxia during menstrual vasoconstriction.113
Evidence supporting a heritable basis for fibroid development derives from epidemiologic studies of fibroids in families and in groups with different racial ethnicity.124
Close family members of women with fibroids have more than double the risk of developing fibroids themselves,129 and African American women are about 3 times more
likely to develop fibroids than White women, irrespective of other factors such as
age, body mass index, parity, and so forth.130,131 More recently, searches for the
mutations underlying these patterns of inheritance have identified specific heritable
genetic polymorphisms associated with development of fibroids in some populations
of women.132,133
Prevalence
A meta-analysis of studies that used SHG or hysteroscopy found fibroids in 4.5% of
the patients with RPL (see Table 5C). This analysis included only submucosal fibroids,
defined earlier as fibroids that distort the uterine cavity. Commonly cited studies of
fibroid prevalence have reported frequencies of 70% or more among the general population, but those rates include all fibroids, regardless of size or location.130,134 When 1
study130 tallied only the clinically relevant fibroids (eg, submucosal fibroids, or fibroids
4 cm in diameter), the prevalence declined to 35% to 50%. Another consideration
of these studies is that they measured fibroids in patients who were predominantly
Uterine Factors
30 to 50 years of age.130,134 The prevalence of fibroids increases with age among premenopausal women,130,131 so greater frequencies of fibroids are likely to occur among
women in these older cohorts than among women seeking treatment of RPL, whose
mean age is about 29 to 34 years.5,57,58,91 Fibroid prevalence among younger women
in the general population is only 5% to 15%,135–137 and 1 study that reported the
breakdown of different fibroid types among 101 women 18 to 30 years old observed
no submucosal fibroids.137 Compared with this finding, a rate of 4.5% submucosal
fibroids among women with RPL is increased.
First-trimester pregnancy loss
Two systematic reviews reported that submucosal fibroids significantly increase the
rate of miscarriages.138,139 Although neither review specified whether the losses
occurred in the first trimester or later, the miscarriage rate for women with fibroids
was as high as 47%.138 Both reviews also reported that miscarriage rates were
increased in women with intramural fibroids; however, when studies using less accurate diagnostic techniques were excluded in 1 review, no effect was seen.139 No effect
of intramural fibroids on miscarriage rate was found in a systematic review of women
undergoing IVF.140 Among women with RPL who had fibroids distorting the uterine
cavity, 42% of pregnancies ended in first-trimester loss.141
The mechanisms by which fibroids might trigger first-trimester miscarriage are not
known. One hypothesis is that the abnormal ultrastructural properties of myocytes in
fibroids and the surrounding myometrium might cause irregular contractions, which
lead to pregnancy loss.114 Most studies have focused instead on endometrial changes
that contribute to implantation failure and infertility (Box 3), but it is possible that some
of these changes may play a role in disrupting pregnancy in women with RPL. An underlying fibroid may exert a deleterious effect on the endometrium either through a
mechanical stimulus, if the fibroid impinges on the cavity, or a molecular one, such
as the inhibitory effect of fibroid transforming growth factor b3 on endometrial expression of molecules involved in implantation.142,143
Treatment options
The options for treatment of fibroids depend on the location, number, and size of the
fibroids, and on the desire of the patient for future reproductive opportunities.8
Because subserosal and intramural fibroids are not considered likely factors contributing to RPL, this section focuses only on treatment of submucosal fibroids, defined
earlier as fibroids that project into the uterine cavity, with or without intramural penetration. Hysterectomy and medical therapies are not included, because neither is
considered an option for a woman who desires future fertility.8
Box 3
Examples of endometrial changes that contribute to implantation failure and infertility in
uteri with fibroids as reviewed by Makker and Goel144
Altered expression of cytokines and other regulatory molecules and receptors (eg,
thrombomodulin)143
Accumulation of inflammatory cells (eg, macrophages)145
Architectural changes (eg, degeneration of glandular structure)142
Data from Makker A, Goel MM. Uterine leiomyomas: effects on architectural, cellular, and
molecular determinants of endometrial receptivity. Reprod Sci 2013;20:631–8.
75
76
Jaslow
Myomectomy is the surgery commonly recommended for women with symptomatic
submucosal fibroids who also wish to bear a child146; however, there is conflicting evidence whether myomectomy can significantly reduce the risk of pregnancy loss in
women with RPL. Of 3 studies that compared the rate of first-trimester miscarriage
(<12 weeks) in women with RPL before and after myomectomy, 2 reported significant
declines in miscarriage rate, but the third found no difference.141,147,148 According to a
recent Cochrane review, there is only 1 randomized controlled trial that has examined
the effect of myomectomy on first-trimester miscarriage rate.149 In this study of 94
infertile women with submucosal fibroids 4 cm or less, women who had undergone
a myomectomy experienced a 43% miscarriage rate (9 miscarriages/21 pregnancies)
compared with the control patients with fibroids who did not have surgery and who
experienced a 56% miscarriage rate (5 miscarriages/9 pregnancies).150 Thus, myomectomy for submucosal fibroids seems to lower the first-trimester miscarriage
rate, but the outcomes are not significantly different (c2 5 0.41, P 5 .523). Normally,
randomized controlled trials are characterized as the highest level of evidence. However, the Cochrane review graded this study to have very low quality of evidence, in
part because the sample size is so small and because different techniques (laparotomy and hysteroscopy) were used to perform the myomectomies.
Hysteroscopic myomectomy is recommended for submucosal fibroids that are
5 cm or less in diameter, although the procedure may necessitate additional steps
if more than half of the fibroid is intramural.8 A comprehensive review by Di Spiezio
Sardo and colleagues151 evaluated the numerous myomectomy techniques that
may be considered, depending on the characteristics of the fibroids and the training
of the surgeon, and discussed operative and postoperative complications. For
women with RPL, complications that may affect future attempted pregnancies
include the formation of intrauterine adhesions and the risk of uterine rupture during
pregnancy.151
Nonhysteroscopic myomectomy may be considered in certain cases. A vaginal
approach may be preferred if the fibroid penetrates the cervical canal.8 If a submucosal fibroid is transmural, or if a hysteroscopic approach might damage too much of the
endometrium, then an abdominal approach (eg, laparoscopy) might be used.8 Several
recent reviews have discussed in detail the advantages and disadvantages of the
different types of nonhysteroscopic surgeries.8,146
Uterine artery embolization destroys fibroids by restricting their blood supply.8,146 It
is not recommended for patients with RPL, because it may cause amenorrhea and
endometrial changes and was found to increase the risk of miscarriages compared
with patients with fibroids who had not had treatment.8,152
Energy-based ablation uses energy sources such as radiofrequency-generated
heat or magnetic resonance–guided ultrasonic waves to destroy fibroids; recent reviews have provided additional information about these procedures.8,146
Expectant management may be considered, particularly given the lack of definitive
data in support of a specific treatment. The greatest problem with this approach is that
women get older with each consecutive loss, and age increases not only the risk of
miscarriage but also the likelihood of developing fibroids.63,130,131
Submucosal fibroids increase rates of miscarriage, although the mechanism
responsible for this is unknown.
Fibroid development is polygenic and multifactorial. Estrogen, progesterone, growth
factors, and other autocrine signaling molecules can promote fibroid growth.
For women with early RPL who have submucosal fibroids, myomectomy should
be considered if no other causes have been identified.
Uterine Factors
Polyps
Characteristics and classification
Polyps are benign growths of the endometrium, containing both glandular and stromal elements, including blood vessels. As described by Peterson and Novak,153
polyps may be sessile, with a thick and plaquelike base or pedunculated, sometimes
extending into or through the cervix. In their study, multiple polyps were found in 22%
of the 616 uteri examined, and the size of any 1 polyp ranged from 0.3 to 12 cm.
Polyps may have a functional endometrium, which responds to ovarian hormones
in the manner of the surrounding endometrium, or may have an endometrium that
is nonresponsive.153
Cause
Increased age and obesity are risk factors for polyps in premenopausal women.154,155
Although there is no evidence of a heritable basis for polyps within families, polyps
can show some characteristic chromosomal abnormalities. A cytogenetic study of
33 polyps found that 57% showed rearrangements in chromosomes 6 (6p21–22),
12 (12q13–15), and 7 (7q22).156 These rearrangements are aberrations of the same
chromosomal regions as those reported for fibroids, and all of these sites contain regulatory genes such as HMG.113,156 Possibly, the same chromosomal anomalies in
polyps and fibroids are a consequence of their common origin from invaginating cells
of the embryonic coelomic epithelium.156
Like fibroids, polyps proliferate in response to estrogen and progesterone, growth
factors, and other cytokines.10,157 Increased aromatase activity within polyps may
also contribute to growth through local production of estrogen.158 Because polyps
arise from endometrial tissue, which requires a complex balance of hormonal signals
for its cyclical growth and degeneration, polyp growth is believed to be promoted by
shifts in the relative expression of estrogen and progesterone receptors.10,157 Also,
data reviewed by Indraccolo and colleagues157 suggest that polyp growth may be
tied to cytokines that promote angiogenesis or to factors that inhibit normal
apoptosis of the endometrium. Evidence in support of a specific mechanism is
ambiguous, possibly because studies have not always accounted for differences in
the expression of receptors and other proteins between the epithelium and the
stroma of the polyps, or for differences in expression related to various stages of
the menstrual cycle.10
Prevalence
A meta-analysis of studies that used SHG or hysteroscopy to diagnose polyps reported
them in 2.4% of the patients with RPL (see Table 5D), making them the least common
of the acquired uterine anomalies. In contrast, SHG examinations of asymptomatic
premenopausal women (ie, women without abnormal uterine bleeding) found polyps
in 7.6% (17/225) of women aged 20 years or older,154 and in 10% (10/100) of women
aged 30 years or older.159 Because polyp prevalence increases with age,154 this complicates comparisons among investigations that use patients of different ages.
First-trimester pregnancy loss
Several studies, including a randomized controlled trial, have linked endometrial
polyps to infertility.160 In contrast, the role of polyps in pregnancy loss has received
little attention. Polyps are often lumped together with fibroids as contributors to
miscarriage (eg, Devi Wold and colleagues161), and most studies of acquired uterine
anomalies and RPL have reported them.45,57,58,91 Clearly, there is a need to investigate the role that polyps might play in women with pregnancy loss.
77
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Jaslow
Treatment options
A 2013 Cochrane systematic review of the effectiveness of polypectomy for infertile or
subfertile women found only 1 randomized controlled trial, which did not report the
impact of the surgery on miscarriage rate.162 Two retrospective studies found no difference in first-trimester miscarriage rates between IVF patients who had received a
polypectomy and those who had not; however, each investigation analyzed only 11
or fewer pregnancies per group.163,164 As a result, these data were underpowered
and less likely to reveal a statistically significant difference. If polyps are found in a
workup for women with RPL and no other known cause, a polypectomy may be
considered if the polyp is greater than 1 cm.10,29 This size criterion is suggested
because smaller polyps have been observed to regress in some patients.165
Methods of polyp removal reviewed by Salim and colleagues10 include blind D&C,
and also hysteroscopy with different techniques and tools for extracting the polyps.
Given the risk of developing adhesions after D&C, and the reported ineffectiveness
of D&C for removing polyps, one of the hysteroscopic resection techniques should
be performed, based on the availability of equipment and training of the surgeon.10
Polyp growth is affected by a balance of estrogen, progesterone, growth factors,
and other autocrine signaling molecules, and factors that cause angiogenesis or
inhibit apoptosis may affect polyp growth.
Given the paucity of published data, there is a need for investigations concerning
the role of polyps in first-trimester pregnancy loss, recurrent or otherwise.
Hysteroscopic polypectomy may be considered for women with RPL if the polyp
is large and no other causes have been found.
SUMMARY
Uterine anomalies are one of the most common factors associated with RPL. Congenital anomalies, such as bicornuate, unicornuate, didelphic, and septate uteri, most
likely result from HOX mutations in the developing Müllerian duct. Of the acquired
uterine anomalies, adhesions are typically formed after endometrial trauma, such as
curettage, whereas fibroids and polyps are benign growths of the myometrium and
endometrium, respectively. Many studies have explored the effects of uterine anomalies with respect to reproductive outcomes, but there are few randomized controlled
trials, particularly for patients with RPL, and treatment methods lack strong supporting
evidence. Nonetheless, metroplasty to correct a septate uterus and surgical removal
of severe adhesions are recommended, and myomectomy of submucosal fibroids
should be considered if no other causes have been identified.
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121. Suo G, Jiang Y, Cowan B, et al. Platelet-derived growth factor C is upregulated
in human uterine fibroids and regulates uterine smooth muscle cell growth. Biol
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122. Murase E, Siegelman ES, Outwater EK, et al. Uterine leiomyomas: histopathologic features, MR imaging findings, differential diagnosis, and treatment. Radiographics 1999;19:1179–97.
123. Bajekal N, Li TC. Fibroids, infertility and pregnancy wastage. Hum Reprod Update 2000;6:614–20.
124. Ligon AH, Morton CC. Genetics of uterine leiomyomata. Genes Chromosomes
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125. Brosens I, Deprest J, Dal Cin P, et al. Clinical significance of cytogenetic abnormalities in uterine myomas. Fertil Steril 1998;69:232–5.
126. Rein MS, Powell WL, Walters FC, et al. Cytogenetic abnormalities in uterine
myomas are associated with myoma size. Mol Hum Reprod 1998;4:83–6.
Uterine Factors
127. Asada H, Yamagata Y, Taketani T, et al. Potential link between estrogen receptoralpha gene hypomethylation and uterine fibroid formation. Mol Hum Reprod
2008;14:539–45.
128. Linder D, Gartler SM. Glucose-6-phosphate dehydrogenase mosaicism: utilization as a cell marker in the study of leiomyomas. Science 1965;150:
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129. Vikhlyaeva EM, Khodzhaeva ZS, Fantschenko ND. Familial predisposition to
uterine leiomyomas. Int J Gynaecol Obstet 1995;51:127–31.
130. Baird DD, Dunson DB, Hill MC, et al. High cumulative incidence of uterine leiomyoma in black and white women: ultrasound evidence. Am J Obstet Gynecol
2003;188:100–7.
131. Marshall LM, Spiegelman D, Barbieri RL, et al. Variation in the incidence of uterine leiomyoma among premenopausal women by age and race. Obstet Gynecol
1997;90:967–73.
132. Eggert SL, Huyck KL, Somasundaram P, et al. Genome-wide linkage and association analyses implicate FASN in predisposition to uterine leiomyomata. Am J
Hum Genet 2012;91:621–8.
133. Hodge JC, T Cuenco K, Huyck KL, et al. Uterine leiomyomata and decreased
height: a common HMGA2 predisposition allele. Hum Genet 2009;125:257–63.
134. Cramer SF, Patel A. The frequency of uterine leiomyomas. Am J Clin Pathol
1990;94:435–8.
135. Borgfeldt C, Andolf E. Transvaginal ultrasonographic findings in the uterus and
the endometrium: low prevalence of leiomyoma in a random sample of women
age 25-40 years. Acta Obstet Gynecol Scand 2000;79:202–7.
136. Laughlin SK, Baird DD, Savitz DA, et al. Prevalence of uterine leiomyomas in the
first trimester of pregnancy: an ultrasound-screening study. Obstet Gynecol
2009;113:630–5.
137. Marsh EE, Ekpo GE, Cardozo ER, et al. Racial differences in fibroid prevalence
and ultrasound findings in asymptomatic young women (18-30 years old): a pilot
study. Fertil Steril 2013;99:1951–7.
138. Klatsky PC, Tran ND, Caughey AB, et al. Fibroids and reproductive outcomes: a
systematic literature review from conception to delivery. Am J Obstet Gynecol
2008;198:357–66.
139. Pritts EA, Parker WH, Olive DL. Fibroids and infertility: an updated systematic
review of the evidence. Fertil Steril 2009;91:1215–23.
140. Sunkara SK, Khairy M, El-Toukhy T, et al. The effect of intramural fibroids without
uterine cavity involvement on the outcome of IVF treatment: a systematic review
and meta-analysis. Hum Reprod 2010;25:418–29.
141. Saravelos SH, Yan J, Rehmani H, et al. The prevalence and impact of fibroids
and their treatment on the outcome of pregnancy in women with recurrent
miscarriage. Hum Reprod 2011;26:3274–9.
142. Deligdish L, Loewenthal M. Endometrial changes associated with myomata of
the uterus. J Clin Pathol 1970;23:676–80.
143. Sinclair DC, Mastroyannis A, Taylor HS. Leiomyoma simultaneously impair endometrial BMP-2-mediated decidualization and anticoagulant expression through
secretion of TGF-beta3. J Clin Endocrinol Metab 2011;96:412–21.
144. Makker A, Goel MM. Uterine leiomyomas: effects on architectural, cellular, and
molecular determinants of endometrial receptivity. Reprod Sci 2013;20:631–8.
145. Miura S, Khan KN, Kitajima M, et al. Differential infiltration of macrophages and
prostaglandin production by different uterine leiomyomas. Hum Reprod 2006;
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146. Guo XC, Segars JH. The impact and management of fibroids for fertility: an
evidence-based approach. Obstet Gynecol Clin North Am 2012;39:521–33.
147. Roy KK, Singla S, Baruah J, et al. Reproductive outcome following hysteroscopic myomectomy in patients with infertility and recurrent abortions. Arch Gynecol
Obstet 2010;282:553–60.
148. Shokeir TA. Hysteroscopic management in submucous fibroids to improve
fertility. Arch Gynecol Obstet 2005;273:50–4.
149. Metwally M, Cheong YC, Horne AW. Surgical treatment of fibroids for subfertility.
Cochrane Database Syst Rev 2012;(11):CD003857.
150. Casini ML, Rossi F, Agostini R, et al. Effects of the position of fibroids on fertility.
Gynecol Endocrinol 2006;22:106–9.
151. Di Spiezio Sardo A, Mazzon I, Bramante S, et al. Hysteroscopic myomectomy: a
comprehensive review of surgical techniques. Hum Reprod Update 2008;14:101–19.
152. Homer H, Saridogan E. Uterine artery embolization for fibroids is associated
with an increased risk of miscarriage. Fertil Steril 2010;94:324–30.
153. Peterson WF, Novak ER. Endometrial polyps. Obstet Gynecol 1956;8:40–9.
154. Dreisler E, Stampe Sorensen S, Ibsen PH, et al. Prevalence of endometrial
polyps and abnormal uterine bleeding in a Danish population aged 20-74 years.
Ultrasound Obstet Gynecol 2009;33:102–8.
155. Onalan R, Onalan G, Tonguc E, et al. Body mass index is an independent risk
factor for the development of endometrial polyps in patients undergoing
in vitro fertilization. Fertil Steril 2009;91:1056–60.
156. Dal Cin P, Vanni R, Marras S, et al. Four cytogenetic subgroups can be identified
in endometrial polyps. Cancer Res 1995;55:1565–8.
157. Indraccolo U, Di Iorio R, Matteo M, et al. The pathogenesis of endometrial
polyps: a systematic semi-quantitative review. Eur J Gynaecol Oncol 2013;34:
5–22.
158. Maia H Jr, Pimentel K, Silva TM, et al. Aromatase and cyclooxygenase-2 expression in endometrial polyps during the menstrual cycle. Gynecol Endocrinol
2006;22:219–24.
159. Clevenger-Hoeft M, Syrop CH, Stovall DW, et al. Sonohysterography in premenopausal women with and without abnormal bleeding. Obstet Gynecol 1999;94:
516–20.
160. Perez-Medina T, Bajo-Arenas J, Salazar F, et al. Endometrial polyps and their
implication in the pregnancy rates of patients undergoing intrauterine insemination: a prospective, randomized study. Hum Reprod 2005;20:1632–5.
161. Devi Wold AS, Pham N, Arici A. Anatomic factors in recurrent pregnancy loss.
Semin Reprod Med 2006;24:25–32.
162. Bosteels J, Kasius J, Weyers S, et al. Hysteroscopy for treating subfertility associated with suspected major uterine cavity abnormalities. Cochrane Database
Syst Rev 2013;(1):CD009461.
163. Check JH, Bostick-Smith CA, Choe JK, et al. Matched controlled study to evaluate the effect of endometrial polyps on pregnancy and implantation rates
following in vitro fertilization-embryo transfer (IVF-ET). Clin Exp Obstet Gynecol
2011;38:206–8.
164. Lass A, Williams G, Abusheikha N, et al. The effect of endometrial polyps on outcomes of in vitro fertilization (IVF) cycles. J Assist Reprod Genet 1999;16:410–5.
165. Lieng M, Istre O, Sandvik L, et al. Prevalence, 1-year regression rate, and clinical significance of asymptomatic endometrial polyps: cross-sectional study.
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M i d - Tri m e s t e r Preg n a n c y L o s s
Kelly M. McNamee, MBChBa,*, Feroza Dawood, MBChB, MRCOG, MDa,
Roy G. Farquharson, MD, FRCOGb
KEYWORDS
Mid-trimester loss Late pregnancy loss Recurrent miscarriage
Miscarriage investigations Antiphospholipid syndrome Bacterial vaginosis
Cerclage
KEY POINTS
Women with mid-trimester pregnancy loss (MTL) represent a heterogeneous group, with
widely varying presentations and origins.
An implemented protocol with standardized investigations is essential to identify any potential cause for an MTL.
Consideration for transabdominal cerclage requires appropriate patient selection.
An MTL may have more than one cause; the presence of dual or even triple pathology increases the risk of a further MTL or preterm delivery dramatically.
Well-designed trials to study MTL are required to establish robust evidence-based practice and improve the treatment and care clinicians can provide.
INTRODUCTION
Mid-trimester loss (MTL) is defined as a pregnancy loss between 12 and 24 weeks’
gestation.1 The true incidence of this complication is difficult to ascertain, because
no accurate data collection has been published.2 It is estimated to affect 2% to
3% of recognized pregnancies.3 MTL has often been classified together with first
trimester losses or omitted altogether. An overlap also exists among MTL, preterm delivery (PTD), and preterm prelabor rupture of membranes (PPROM), and these conditions may often be a continuum of associated factors. The distinction between MTL
and PTD is defined as the gestation of fetal viability (currently 24 weeks’ gestation);
both complications are known to have a similar origin.4
A dearth of knowledge exists regarding the optimal treatment and investigations for
a distinct MTL cohort. Women who have an MTL represent a heterogeneous group,
displaying widely varying presentations and origins.2 Causative factors include
Funding Sources: None.
Conflicts of Interest: None.
a
Department of Obstetrics, Liverpool Women’s Hospital, Crown Street, Liverpool L8 7SS, UK;
b
Department of Gynaecology, Liverpool Women’s Hospital, Crown Street, Liverpool L8 7SS, UK
* Corresponding author.
E-mail address: kellymcnamee@doctors.org.uk
Obstet Gynecol Clin N Am 41 (2014) 87–102
http://dx.doi.org/10.1016/j.ogc.2013.10.007
obgyn.theclinics.com
0889-8545/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
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antiphospholipid syndrome (APS), cervical weakness, infection, placental insufficiency, and congenital uterine anomalies (CUAs). Despite this, the cause remains unknown in 50% to 60% of women.1–3,5 An important consideration is that an MTL may
have more than one cause. The presence of dual or even triple pathology dramatically
increases the risk of a further MTL or PTD.
An implemented protocol with standardized investigations is essential to identify
any potential cause for an MTL. Classifying pathology is important for determining
future pregnancy management, especially in the presence of repeated MTL.
SCREENING PROTOCOL
When investigating a woman with a history of an MTL, a thorough objective approach
is required. An accurate clinical event history can often expose a potential cause
(Table 1). A detailed family history can identify hereditary factors, such as thrombophilia or chromosomal translocation, thus guiding appropriate evaluation. Complex
maternal illnesses, such as poorly controlled diabetes, uncontrolled hypertension,
and thrombophilia, have been known to cause MTL. Poorly controlled thyroid disease
is also associated with MTL and PTD; however, if the maternal disease has contributed to a pregnancy complication, confirmation should be sought as evidence (ie,
placental pathology).5 A sudden asymptomatic intrauterine death can be associated
with APS, whereas cervical weakness classically presents as silent cervical dilatation
with evidence of fetal heart activity. Infection can present as spontaneous rupture of
membranes with a closed cervix.2
A clinical event picture can be mixed and difficult to interpret. Occasionally,
women with more than one MTL can describe very different histories emphasizing
the possibility of dual/triple pathology. Differing causal factors can predominate at
different gestations in different pregnancies within the same individual.2 Although a
local investigative audit showed the distribution of pathology, it may not be truly representative of all MTLs because of referral bias (Fig. 1).
After a detailed history, a series of investigations should be performed (Fig. 2). Diagnosis of APS can be complex and is usually a combination of clinical manifestation and
presence of lupus anticoagulant and/or anticardiolipin antibodies.6 With a history of
MTL, a high vaginal swab (HVS) can diagnose/exclude possible infection. A repeated
HVS is recommended in the first trimester of a subsequent pregnancy to exclude
bacterial vaginosis (BV), the presence of which may fluctuate over time. The Nugent
criteria are used because they include an intermediate-flora classification characterized by abnormal genital-tract colonization that may be a transition stage on the
way to full-fledged BV.7 The cervix may be evaluated with a transvaginal ultrasound
to measure cervical length and with hysteroscopy, but assessment also requires a
convincing history. CUAs can also be diagnosed through ultrasound (3-dimensional
if facilities allow) and/or hysteroscopy.
Table 1
Clinical history sequence
Event vs Factor
Cervix
Liquor Present on Vaginal
Speculum Examination
Cervical weakness
Open
Absent until expulsion of sac
Present
Thrombophilia/APS
Closed
Absent
Absent
Bacterial vaginosis
Closed
Present
?Present until sac expulsion
Fetal Heart Activity
Mid-Trimester Pregnancy Loss
Fig. 1. Distribution of cause in 351 consecutive cases of MTL at Liverpool Women’s Hospital.
Whether a previous MTL was a consequence of a chromosomal abnormality or fetal
anomaly is advantageous to determine. Previous amniocentesis or postmortem results can potentially eliminate causative pathology. Increasing consensus is favoring
full cytogenetic testing with array comparative genomic hybridization and fluorescent
Fig. 2. Investigation protocol for MTL. ACA, Anti-cardiolipin antibody; ANA, antinuclear
antibodies; DRVVT, Dilute Russell’s viper venom time; dsDNA, double stranded Deoxyribonucleic acid; E2, Oestradiol; ENA, Extractable nuclear antigens; FSH, Follicular stimulating hormone; Hb, Haemoglobin; IgG, Immunoglobulin G; IgM, Immunoglobulin M; La, anti-La
antibodies; LH, Luteinising hormone; RO, anti-Ro antibodies; SMA, Anti-Smith antibodies;
WCC, White cell count. (Adapted from Farquharson RG. Late pregnancy loss. In: Farquharson
RG, Stephenson MD, editors. Early pregnancy. Cambridge: Cambridge University Press; 2010.
p. 277–86; with permission.)
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in situ hybridization for all women who have experienced pregnancy losses. Debate
exists as to whether the success or failure of a treatment in a previous pregnancy
loss can ever be defined without accurate cytogenetic analysis. The chromosomal
analysis of a miscarriage can be an informative diagnostic tool for patient counseling
and subsequent pregnancy management.8
MTL–ASSOCIATED PATHOLOGY
APS
APS is associated with miscarriage in any trimester. It was first described in the early
1980s as a unique form of autoantibody-induced thrombophilia associated with pregnancy complications. The antibodies involved promote activation of the endothelial
cells, monocytes, and platelets. As a consequence, tissue factor and thromboxane
A2 is overproduced.9 The most common obstetric manifestation is fetal loss; however,
other features include preeclampsia and placental insufficiency, prompting delivery.10
The hypothesis behind APS and pregnancy loss is the encouragement of a prothrombotic environment. Microthrombi are common in the placental vasculature and
decidua in pregnancy samples from patients who experienced recurrent miscarriages.11 APS can cause pregnancy loss before the growth and development of the
placental vasculature. Inflammation is a significant component of APS pathogenesis,
as demonstrated in recent mice studies showing a pivotal role of complement activation in thrombosis and fetal loss induced by antiphospholipid antibodies.12 Although
existing literature suggests that women with APS are more likely to experience a fetal
loss in the first trimester,13 convincing evidence shows that pregnancy complications
are most prevalent in late pregnancy,14 with one study reporting APS in 42% of a
cohort with a history of MTL.15
TREATMENT
Guidelines are in place for the treatment of positively diagnosed APS with thromboprophylactic medication.16–19 Regular surveillance is recommended throughout the
pregnancy. Close observation for maternal hypertension and proteinuria, in addition
to appropriate fetal growth surveillance with ultrasound, is advised in the second
and third trimesters. Doppler assessments are widely used in Europe to assess for
preeclampsia, placental insufficiency, and fetal growth restriction.9
Recent well-designed studies have been a welcome addition to previous recommended treatment. Aspirin is commonly used as a treatment for recurrent miscarriages, even those deemed idiopathic. Two randomized controlled trials have
compared aspirin with placebo or supportive care in women with APS,20,21 but no significant difference was found in the defined outcomes. A Cochrane review concluded
that combined unfractionated heparin (UFH) and aspirin may reduce pregnancy loss
by 54%, yet randomized controlled trials with adequate allocation concealment are
needed to explore potential differences between UFH and low-molecular-weight heparin (LMWH).22
Two further well-designed studies comparing aspirin alone versus aspirin plus
LMWH in women with APS found no differences in live birth rates and miscarriages.23,24
INFECTION
Infection seems to have a role in causing miscarriage in the mid-trimester rather
than the first trimester.25 A retrospective study of placental histology of more than
7000 spontaneous deliveries demonstrated histologic chorioamnionitis in 94% before
Mid-Trimester Pregnancy Loss
24 weeks’ gestation compared with 40% between 25 and 28 weeks and 11% after
33 weeks.26 Similar results were found in a case-control study, wherein chorioamnionitis was diagnosed in 77% of spontaneous MTLs compared with no infection found in
the control group (induced labor for fetal anomaly).27 However, the appearance of
chorioamnionitis may well be secondary to a primary insult in an unknown number
of cases previously described.
Microorganisms associated with preterm birth have been shown to play a key role in
MTL. Chorioamnionitis involves organisms such as anaerobic streptococci, enterococci, coliforms, staphylococci, Fusobacterium spp, Mycoplasma spp, Ureaplasma
spp, and group B b-hemolytic streptococci.28 The most common pathway for an intrauterine infection is the ascent from the cervix and vagina.
Bacterial vaginosis is prevalent in up to 50% of pregnant women29 and is considered a risk factor for PTD, PPROM, and MTL.30 Bacterial vaginosis is an imbalance
of vaginal flora caused by a reduction of the normal lactobacillary bacteria, and a
heavy overgrowth of mixed anaerobic flora, including Gardnerella vaginalis, Mycoplasma hominis, and Mobiluncus species.
Classical diagnosis of BV31 is known to be complex and time-consuming. A less
strict inclusion system, the Nugent’s classification, is now more widely used,
because it includes an intermediate-flora classification characterized by abnormal
genital-tract colonization that may represent a progression to full BV.7 Ideally, an
HVS should be performed in the first quarter of the menstrual cycle when levels
are highest.2
Evidence shows that an intermediate-flora diagnosis has an association with
adverse pregnancy outcome.32 The influence of sexually transmitted diseases
(STDs), with or without BV, on adverse pregnancy outcome has not been clearly
defined.33 Literature suggests that Trichomonas vaginalis is associated with BV and
PPROM.34 Chlamydia trachomatis in conjunction with BV has been found to increase
the rate of PTL.35
TREATMENT
Treatment of intermediate abnormal vaginal flora and BV has been shown to reduce
the occurrence of MTL.36 Debate exists regarding the timing of optimal treatment of
abnormal vaginal flora and BV. Results from 5 trials in the Cochrane review4 are
encouraging, showing a reduction in PTD when treated before 20 weeks.
Commencing antibiotics early in the second trimester is highly recommended37; however, little research has been performed on the best possible route or dose.
Results of a large trial randomizing 624 women positive for BV and at high risk of
PTD to either metronidazole and erythromycin or placebo showed that treatment
with antibiotics reduced the rate of PTD.38 The ORACLE II trial39 compared the use
of erythromycin and/or amoxicillin-clavulanate (co-amoxiclav) versus placebo in
women in spontaneous preterm labor and intact membranes with no overt signs of
clinical infection. The aim of the ORACLE Children Study II was to determine the
long-term effects on children after exposure to antibiotics in this clinical situation.
The authors advocate caution when using erythromycin in pregnancy due to an
observed increase in the rate of cerebral palsy.40 Used in isolation, metronidazole is
less efficacious because of its narrow range of activity against BV organisms.
Clindamycin therapy for BV or intermediate vaginal flora, when initiated early in the
second trimester, has been shown to significantly reduce MTL.36,41,42 Two large randomized controlled trials used a course of either 300 mg of oral clindamycin36 or 5 g of
2% intravaginal clindamycin pessaries.41 Both studies emphasize the importance of
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early screening and treatment. The current preferred regimen is a 7-day course of 2%
clindamycin cream vaginally (5 g of cream containing 100 mg of clindamycin phosphate).43 Even though oral administration is straightforward, fewer systematic side effects may occur with the intravaginal route. Little evidence supports screening of the
general obstetric population for BV and abnormal vaginal flora in the absence of a history of MTL/PTD.
UTERINE ANOMALY
Uterine anomalies can be grouped into congenital (disorders of the müllerian tract) or
acquired (adhesions or leiomyomas). Although some uterine defects may have no
impact on pregnancy outcome, others may contribute to miscarriage, intrauterine
growth restriction, and PTL.44,45
CUAs are rare, and a lack of consistency exists regarding their clinical significance
and optimal management. The true population prevalence is difficult to assess,
because no universally accepted standardized classification system exists and diagnostic techniques tend to be invasive. As a result, prevalence rates in the literature can
vary between 0.06% and 38.00%.
A recent literature review evaluating the presence of CUAs in high-risk women
reported a prevalence of 13.3% among women with a history of miscarriage.46
CUAs arise from the failure of the müllerian tract to complete bilateral duct elongation, fusion, canalization, or septal resorption of the müllerian ducts (Table 2).47
An abundance of studies have described CUA and miscarriage rates; however, few
differentiate between early pregnancy loss and MTL. No specific study has researched
unicornuate and bicornuate uterus in association with MTL.5 A recent case-control
study found that women with an arcuate uterus are not at any greater risk of MTL.
Nonetheless, the study suggests a 3-fold increased risk of an MTL with a diagnosed
septate or bicornuate uterus.48 One hypothesis is that of an altered intrauterine pressure, not found in an arcuate uterus, that would contribute to subsequent myometrial
and cervical dysfunction.48 Further trials are required to explore the relationship
between CUAs and MTL.
DIAGNOSIS
CUAs are typically diagnosed using ultrasound, hysterosalpingography, or under
direct vision with hysteroscopy. Laparoscopy and magnetic resonance imaging
can also be performed. Three-dimensional (3D) ultrasound has the advantage of
being noninvasive and allows complete assessment of uterine morphology. Uterine
dimensions can be measured, thus evaluating the likely success of any surgical intervention.47 In several studies, 3D ultrasound has compared favorably to hysterosalpingography and laparoscopy for diagnosing CUAs.49,50
TREATMENT
Controversy surrounds the benefit of surgical uterine correction. Uncertainty exists
about the efficacy of hysteroscopic surgical resection/metroplasty of the subseptate
uterus. Although several uncontrolled small studies have claimed improvements in
future pregnancies after resection,51,52 no randomized controlled trials support these
observations. An increased rate of obstetric complications has been described after
hysteroscopic metroplasty, such as fetal malpresentation at term and an increased
rate of delivery by caesarean section.53
Mid-Trimester Pregnancy Loss
Table 2
American Society of Reproductive Medicine (previously American Fertility Society)
classification of anomalies of the müllerian duct
Classification
Clinical Finding
Description
I
Segmental or complete
agenesis or hypoplasia
Agenesis and hypoplasia may involve the
vagina, cervix, fundus, tubes, or any
combination
Mayer-Rokitansky-Küster-Hauser syndrome is
the most common example in this category
II
Unicornuate uterus with
or without a
rudimentary horn
When an associated horn is present, this class
is subdivided into communicating
(continuity with the main uterine cavity is
evident) and noncommunicating (no
continuity with the main uterine cavity)
The noncommunicating type is further
subdivided based on whether an
endometrial cavity is present in the
rudimentary horn
III
Didelphys uterus
Complete or partial duplication of the
vagina, cervix, and uterus characterizes this
anomaly
IV
Complete or partial
bicornuate uterus
Complete bicornuate uterus is characterized
by a uterine septum that extends from the
fundus to the cervical os
The partial bicornuate uterus demonstrates a
septum, which is located at the fundus
In both variants, the vagina and
cervix each have a single chamber
V
Complete or partial
septate uterus
A complete or partial midline septum is
present within a single uterus
VI
Arcuate uterus
A small septate indentation is present at the
fundus
VII
Diethylstilbestrol-related
abnormalities
A T-shaped uterine cavity with or without
dilated horns is evident
Adapted from The American Fertility Society classifications of adnexal adhesions, distal tubal occlusion, tubal occlusion secondary to tubal ligation, tubal pregnancies, müllerian anomalies and intrauterine adhesions. Fertil Steril 1988;49:944–55; with permission.
Outcomes are anticipated from The Randomised Uterine Septum Transection
(TRUST) trial comparing hysteroscopic metroplasty and expectant management in
the miscarriage population.54
CERVICAL WEAKNESS
True cervical weakness is an accepted cause for MTL and PTD, yet no universal
consensus exists on the definition or appropriate diagnostic testing.55,56 All other
potential causes of MTL must be excluded, because consequential management is
invasive and has associated risks. The inclusion criterion for the Cervical Incompetence Prevention Randomized Cerclage Trial (CIPRACT) was defined as “the initial,
painless, progressive dilatation of the uterine cervix, where PTD seems inevitable
without interference.”57 The diagnosis is made in the absence of other causes of
PTD, such as uterine anomaly, fibroids, or infection, and only when singleton pregnancies are involved.57 In the nonpregnant state, the passage, without resistance, of a size
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9 Hegar dilator (Medline Industries, Inc., Mundelein, IL, USA) through the cervix, acts
as a surrogate measure.2 An accurate clinical event sequence is paramount to avoid
the overuse of non–evidence-based, ineffective medicine and surgery.
MANAGEMENT
Ultrasound Assessment
Ultrasound assessment of cervical length has emerged as an effective prognosticator
for PTD, especially in women with a previous history.58 Transvaginal cervical length
measurements are far superior and more reliable than digital cervical examination in
assessing the length of the cervical canal, with an interobserver and intraobserver
viability of less than 10%.59
The risk of adverse obstetric outcome is inversely related to the length of the
cervix and the gestational age at detection of a short cervix. Cervical length of
less than 25 mm has been found in most populations to have the best predictive
accuracy for MTL/PTD, and may be the most reliable threshold to define a highrisk population.60,61
A large randomized study screened 47,000 low-risk women for cervical shortening
at 23 weeks’ gestation using transvaginal ultrasound.62 Of these women, 470 had a
cervical length measurement of 15 mm or less and were consequently randomized
to either cerclage or expectant management. The incidence of PTD was similar in
both groups, indicating that ultrasound-indicated cerclage is not beneficial in women
who have an incidental finding of a short cervix, in the absence of a previous MTL/
PTD.63
Conversely, women with a prior obstetric risk may benefit from an ultrasound finding
of a short cervix. A meta-analysis of 4 randomized controlled trials showed that
women with a previous MTL/PTD and a cervical length of less than 25 mm had a higher
rate of pregnancies continuing into the third trimester after insertion of cerclage.64 No
studies have evaluated ultrasound-indicated cerclage performed in the presence of
funneling. Cervical length measurement may also be useful in reassuring and monitoring women who have been treated with cerclage.
PROGESTERONE
Progesterone supplementation has been used for more than 50 years; however,
scientific evidence supporting its efficacy is lacking. The hormone seems to have
anti-inflammatory properties,65 thus preventing cervical ripening.66 Progesterone
can be prescribed in the form of a vaginal pessary or gel, or as an intramuscular injection (17a-hydroxyprogesterone caproate). Extensive literature has described the use
of progesterone in preventing PTD and recurrent miscarriages; however, none has
focused on MTL in isolation. Two randomized controlled trials67,68 and an individual
patient data meta-analysis69 have shown that the rate of PTD is reduced with the
use of vaginal progesterone.
A recent comprehensive literature review of the use of vaginal progesterone and
cervical cerclage in women with a sonographically short cervix found that these
treatments have similar efficacy for preventing PTD. The authors propose that
high-risk obstetric patients be treated with 17a-hydroxyprogesterone caproate
from 16 weeks, followed by cervical length measurements beginning at 18 weeks.
If the cervical length measurement is less than 25 mm, vaginal progesterone should
be offered.70
No guidance exists on the use of progesterone in the prevention of MTL. Suggestions for proposed treatment regimens are extrapolated from studies detailing
Mid-Trimester Pregnancy Loss
previous PTD or short cervical length. Research in the form of well-designed doubleblind studies is required before progesterone supplementation can be evidencebased in the MTL cohort.
TRANSVAGINAL CERVICAL CERCLAGE
The goal of cerclage is to strengthen the internal cervical os to maintain a pregnancy.
In the mid-20th century, Shirodkar71 and McDonald72 described the 2 classical techniques of transvaginal cervical cerclage (TVC). The difference in technique is that with
a Shirodkar cerclage, the bladder is reflected to enable the suture to be placed as
close to the internal cervical os as possible per vaginam. The choice of technique is
usually at the discretion of the surgeon. Evidence shows no significant difference in
PTD rates between the Shirodkar and McDonald techniques.73
RESEARCH EVIDENCE FOR TVC
Cerclage is a common prophylactic intervention for MTL and PTD, despite the lack of
a well-defined population for whom evidence of a clear benefit exists. TVC is not
without risks. The procedure is associated with an increased likelihood of medical
intervention, hospital admission, puerperal pyrexia, induction of labor, and caesarean
section.
The largest study to evaluate the efficacy of TVC included 1292 women at risk of
PTD.74 The authors concluded that women with a history of at least 3 previous
MTLs were the only group to show a benefit from cerclage placement. The overall
risk of PTD decreased from 32% to 15%. Similar results were found in a multicenter
randomized controlled trial; however, the criterion for patient selection was the finding
of a short cervix on routine transvaginal scanning at 22 weeks. Women with a cervix
length of 15 mm or less were randomised to cerclage or expectant management.
The PTD rate before 33 weeks was 22% in the cerclage group compared with
26% in the control group.75
The CIPRACT trial recruited 35 women with a history suggestive of cervical weakness and a cervical length measurement of less than 25 mm before 27 weeks’ gestation. PTD before 34 weeks was 0% in women treated with cerclage compared with
44% in the control group. The authors concluded that therapeutic TVC with bedrest
reduces PTD, but found no statistical difference in neonatal survival.57 A further randomized controlled trial failed to show an improved perinatal outcome with TVC,
suggesting that ultrasonographic dilatation of the internal os and shortening of the
distal cervix is a consequence of pathophysiological processes such as inflammatory
and infective stimuli.76
CERVICAL OCCLUSION
Total cervical occlusion involves closure of the external os using a continuous suture
during the first trimester in addition to the primary TVC. The hypothesized action is that
in conjunction with a TVC, which increases the resistance of a weakened cervix, a
cervical mucus plug may prevent ascending infection, acting as a mechanical and
immunologic barrier.77 A recent multicenter, stratified, randomized controlled trial
recruited 309 women to TVC with or without occlusion. The trial stopped early
because of slow recruitment and an interim analysis that showed no benefit associated with occlusion in terms of gestational age at delivery and admission to the
neonatal intensive care unit.78
95
96
McNamee et al
“If cervical cerclage during gestation is indicated but the vaginal approach is
impossible, why not accomplish constriction from above?”79
TRANSABDOMINAL CERCLAGE
Cases exist in which cervical cerclage has failed or is deemed inappropriate. Examples include the presence of a short or absent cervix after surgery, congenital deformity, and scarring as a consequence of obstetric trauma or previous cerclage. Benson
and Durfee79 first performed a transabdominal cerclage (TAC) in 1965 between 14 and
24 weeks’ gestation. They first performed a midline incision, then opened the broad
ligament, and, after mobilizing the uterine vessels, sought an avascular space through
which to pass a 5-mm Mersilene tape.
A preconceptual interview is crucial for appropriate patient selection. Full disclosure
and considerable explanation must be provided regarding the risks of failure, complications of insertion after previous surgery (eg, classical caesarean delivery; hourglass
constriction of the cervix; damage to adjacent major blood vessels, bowel, or bladder),
and the need for 2 major operations. This discussion should be followed by a second
counseling appointment so the patient is fully informed and understands that a TAC is
the last resort. Inclusion and exclusion criteria are described in Table 3. The procedure
is outlined in Box 1.
RESEARCH EVIDENCE FOR TAC
Currently, no randomized studies have compared the effectiveness of TAC with
expectant management or TVC.63 A systematic review reported a lower delivery
rate before 24 weeks’ gestation in women with a TAC compared with those who
had a repeat TVC.80 These outcomes were reiterated in a further study in which
TAC, rather than TVC, improved PTD rates.81 Results should be viewed with
caution, however, because assignment to either group was at the author’s discretion, no prospective analysis was conducted, and several cases were excluded
from the report.
No study has compared the insertion of TAC preconceptually or during pregnancy.
In the nonpregnant state, the procedure is associated with fewer complications and
the risk of bleeding is reduced. Some case reports have described a laparoscopic
approach to TAC; however, currently no evidence suggests that it is superior.63 In a
recent multicenter cohort study, 66 preconceptual laparoscopic abdominal cerclages
were performed in women with at least one pregnancy loss in the second or third
Table 3
Important preconceptual findings from history, full investigation protocol, and event
sequence analysis
Inclusion Criteria
Exclusion Criteria
Elective vaginal cerclage for the treatment
of cervical weakness failed, causing MTL
Multiple pregnancy
Completion of a full investigation protocol
for MTL
Untreated coexisting cause of recurrent
miscarriage
Cervical length measurement >20 mm on
transvaginal ultrasound
Incomplete investigation protocol
Viable singleton pregnancy
Unwillingness to undergo randomization
of treatment
Mid-Trimester Pregnancy Loss
Box 1
Transabdominal cerclage procedure
Fetal viability confirmed through preprocedure scan (if performed during pregnancy)
Preoperative thromboprophylaxis and intraoperative antibiotics administered
Laparotomy performed between 9 and 13 weeks.
Catheter placed in situ
Vaginal pack placed to elevate uterus and improve access to cervico-isthmic region
Patient placed in the Trendelenburg position
Low transverse abdominal incision performed
Peritoneum of the uterovesical fold incised transversely in the midline
Uterine vessels and isthmus identified digitally
Double-stranded 2-gauge nylon suture mounted onto a loose 40-mm round-bodied Mayo
needle
Isthmus grasped between thumb and forefinger to stabilize the uterus
Suture inserted posteroanteriorly through the window between the substance of the cervix
lateral to the canal but medial to the uterine vessels—the level of the uterine isthmus above
the insertion of the uterosacral ligaments
Needle remounted and procedure repeated posteroanteriorly on opposite side (Fig. 3)
Knot tied anteriorly, covered by loose peritoneal fold
Abdomen closed
Inpatient stay 2 days
Fetal viability scan performed before discharge
TAC left in situ permanently
Adapted from Farquharson RG. Late pregnancy loss. In: Farquharson RG, Stephenson MD,
editors. Early pregnancy. Cambridge (UK): Cambridge University Press; 2010. p. 277–86; with
permission.
Fig. 3. Transabdominal cerclage technique. (Adapted from Farquharson RG. Late pregnancy
loss. In: Farquharson RG, Stephenson MD, editors. Early pregnancy. Cambridge: Cambridge
University Press; 2010. p. 277–86; with permission.)
97
98
McNamee et al
trimester and/or a short or absent cervix. A total of 25 patients (71%) delivered after
34 weeks’ gestation; however, 3 women experienced a further MTL. The perioperative
complication rate was 4.5%. No mention was made of a thorough investigation protocol preceding the cerclage to exclude any other possible condition contributing to
their poor obstetric history.82 A case series of 40 TACs report a success rate of
90% (n 5 36). The 4 cases with adverse outcomes had evidence of other pathologies
contributing to the pregnancy loss (APS and chorioamnionitis).83
The presence of dual pathology, in conjunction with cervical weakness, is associated with a 56% risk of delivery before 34 weeks’ gestation.83 The authors
emphasize the importance of comprehensive screening and counseling when
considering a TAC, especially with a positive diagnosis of other MTL-associated
conditions.
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1424–6.
E n d o c r i n e B a s i s fo r R e c u r re n t
P re g n a n c y Lo s s
Raymond W. Ke,
MD, HCLD
KEYWORDS
Recurrent pregnancy loss Luteal phase defect Hyperprolactinemia
Polycystic ovary syndrome Thyroid disease Thyroid antibodies
KEY POINTS
Common endocrinopathies are a frequent contributor to both spontaneous and recurrent
miscarriage.
Although the diagnostic criteria for luteal phase defect is still controversial, treatment of
patients with both recurrent pregnancy loss and luteal phase defect using progestogen
in early pregnancy appears to be beneficial.
With rising demand, an increase in thyroid gland function is critical in the maintenance of
early pregnancy.
Overt or subclinical hypothyroidism along with the presence of antithyroid antibodies is
correlated with poor obstetric outcome.
Women with polycystic ovary syndrome, the most common endocrinopathy of reproductive age women, have an increased risk of pregnancy loss.
Management of hyperinsulinemia in polycystic ovary syndrome with normalization of
weight or metformin appears to reduce the risk of pregnancy loss.
The human embryo enters the uterine cavity 4 days after ovulation. The process of implantation begins approximately 3 days later or typically between 19 and 23 days from
the last menstrual cycle, a time period of high receptivity known as the implantation
window.1 It has been observed that the longer the ovulation-to-implantation interval,
the higher the risk of early pregnancy loss.2 Endocrine hormones play a critical role
in the expression, modulation, and inhibition of various growth factors, cytokines,
cell adhesions molecules, and decidual proteins. Estradiol and progesterone control
the orderly growth and differentiation of the endometrium for implantation of the
embryo. A receptive endometrium is characterized by growth and coiling of spinal
arteries, secretory changes in the glands, and decidualization of the stromal compartment. Failure of the endometrium to respond to these hormonal signals can result in
The author has nothing to disclose.
Assisted Reproduction, Fertility Associates of Memphis, 80 Humphreys Center, Suite 307,
Memphis, TN 38120, USA
E-mail address: rke@fertilitymemphis.com
Obstet Gynecol Clin N Am 41 (2014) 103–112
http://dx.doi.org/10.1016/j.ogc.2013.10.003
obgyn.theclinics.com
0889-8545/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
104
Ke
defective placentation resulting in a risk of miscarriage. Recurrent pregnancy loss
(RPL), defined as 2 or more consecutive pregnancy losses before the 20th week of
pregnancy, is a frequent obstetric complication. One of the pathogenetic mechanisms
underlying RPL includes a dysfunction of the endocrine system.
LUTEAL PHASE DEFECT
Crucial to the development of the endometrium is adequate glandular growth primarily
mediated by abundant estradiol during the proliferative phase. At a threshold value,
estradiol signals the pituitary to release a large amount of luteinizing hormone (LH)
into circulation. This surge of circulating LH triggers oocyte maturation and release
and the formation of the corpus luteum from the granulosa cells of the ruptured follicular bed. The luteal phase begins with the LH surge and ideally lasts 14 days in a
nonpregnant menstrual cycle ending when hormone withdrawal from the involuting
corpus luteum results in endometrial sloughing and the start of another menstrual cycle. Unique to the luteal phase is a sharp increase in progesterone production from the
corpus luteum that, along with estradiol, peaks during the implantation window. Primarily through the action of progesterone, the endometrium undergoes stromal
decidualization, and the glands switch to a secretory role in preparation for implantation.3,4 A normal luteal phase is characterized by estradiol-mediated glandular growth
in the preceding proliferative phase, adequate LH surge triggering ovulation, followed
by robust progesterone production with an appropriate endometrial response.
Accordingly, the dysfunctional mechanisms resulting in luteal phase defect (LPD),
also known as luteal phase insufficiency, may include poor follicular growth, oligoovulation, inadequate corpus luteum function, or altered endometrial response to
secreted progesterone.3 These mechanisms may arise from a wide spectrum of endocrinopathies and comorbidities such as hyperprolactinemia or stress (Box 1).5 LPD
has long been suspected with miscarriage and RPL.6 However, quantifying the risk
has been hampered by the difficulty in defining diagnostic criteria for LPD.3,4 Although
histologic dating of the endometrium after timed biopsy has been the historical gold
standard for the diagnosis of LPD, the accuracy and reproducibility of this modality
is highly suspect given significant intra- and interobserver variation in interpretation.5,7
In a study of timed endometrial biopsies from 130 fertile women, Murray and colleagues8 found that histologic endometrial dating had neither the accuracy nor the
precision to diagnose LPD and thus did not help in the clinical management of these
patients. A criterion of luteal phase length less than 11 days can be difficult to measure
reliably and document consistently but could be useful as a screening evaluation for
LPD. Luteal phase hormone levels, especially progesterone concentration, are more
Box 1
Identified causes of luteal phase defect
Hyperprolactinemia
Polycystic ovary syndrome
Hypogonadotropic hypogonadism
Poor ovarian reserve
Stress
Exercise
Extreme weight loss
Endocrine Basis for Recurrent Pregnancy Loss
useful if performed serially over the course of the luteal phase to better identify peak
levels. Regardless, hormone levels fluctuate significantly during the day and still may
not reflect endometrial response to a given concentration.9 Given the challenge of variable diagnostic criteria, the incidence of LPD in women with RPL is estimated between 12% and 28%.10,11
The lack of consensus in diagnostic criteria for LPD has made it difficult to arrive at
management recommendations in RPL patients. Treatment options have varied widely
and include luteal phase supplementation using progestogen or human chorionic
gonadotropin (hCG), ovulation induction, or a combination of these. Medication types,
doses, timing and routes of administration have remained contentious. Because a deficiency of progesterone action on the endometrium is arguably the critical feature of
LPD, supplementing the luteal phase with pharmaceutical progestogens has remained
the most common therapy. A Cochrane review of progestogen treatment in 15 studies
found no statistical difference in miscarriage rates between progestogen or placebo
groups.12 However, when the analysis included only the 4 studies that identified
women with 3 or more previous pregnancy losses, a statistically significant reduction
of loss in the women randomly assigned to the progestogen-treated group (Peto
odds ratio, 0.38; 95% confidence interval [CI], 0.20–0.70) was found (Fig. 1).
Hyperprolactinemia is a unique endocrinopathy that causes infertility and miscarriage through anovulation or, in more subtle forms, LPD. Elevated prolactin alters
the hypothalamic-pituitary-ovarian axis leading to impaired folliculogenesis or a short
luteal phase. Often, hyperprolactinemia is secondary to medication use or primary
hypothyroidism. In these cases, correction of prolactin levels through management
of the underlying cause should be attempted. Treatment of women with RPL and
refractory hyperprolactinemia, with a dopamine agonist such as bromocriptine, significantly improved subsequent pregnancy outcome.13
THYROID DISEASE AND PREGNANCY LOSS
Normal pregnancy exerts a dramatic change in thyroid function and regulation. There
is a marked demand for both thyroxine (T4) and triiodothyronine (T3) well greater than
Fig. 1. Meta-analysis of progestogen versus placebo/no therapy for luteal phase defect in
women with 3 or more previous miscarriages. (Adapted from Haas DM, Ramsey PS. Progestogen for preventing miscarriage. Cochrane Database Syst Rev 2008;(2):CD00351; with
permission.)
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that required in the nonpregnant state. Total T4/T3 concentrations increase sharply in
early pregnancy and plateau early in the second trimester at concentrations 30% to
100% greater than prepregnancy values.14 The increased demand for thyroid hormone in pregnancy predominantly arises from a 2- to 3-fold increase in circulating
plasma thyroid binding globulin (TBG) binding to circulating T4/T3 reducing the pool
of bioavailable hormone. TBG production is stimulated by estradiol from the corpus
luteum and eventually the placenta. However, total T4/T3 is still less than would be expected by increased TBG binding resulting in an overall decline in free T4 during pregnancy. Greater demand for hormone production by the thyroid in pregnancy is also the
result of deiodination of thyroxine by the placenta and the initial mild thyrotropic effects of human chorionic gonadotropin (Fig. 2). Therefore, if thyroid homeostasis is
to be maintained in pregnancy, the gland must dramatically increase thyroid hormone
production. The supply of dietary iodine, complicated further by the increase in renal
iodide clearance, is crucial to allow increased production. Preexisting thyroid gland
dysfunction may limit the ability of the gland to meet pregnancy demands.
Despite the known association between decreased fertility and hypothyroidism, the
latter condition is not incompatible with conception. This is probably the main reason,
until a few years ago, hypothyroidism had been considered—wrongly—to be rare during pregnancy. Abalovich and colleagues15 observed that 34% of hypothyroid women
became pregnant without T4 treatment. Of these, 11% suffered overt hypothyroidism,
and 89% had subclinical hypothyroidism. Maternal thyroid-stimulating hormone (TSH)
levels may decline in early pregnancy but otherwise should be maintained in the
normal range through pregnancy. However, there is a debate regarding the normal upper limit of TSH. Whereas TSH values of 4.0 to 5.0 mIU/L were once considered
normal, a consensus is emerging that a TSH value greater than 2.5 mIU/L is outside
the normal range.16
If and when hypothyroid women become pregnant, they carry an increased risk for
early and late obstetric complications (Box 2). A Dutch study of nearly 2500 pregnant
women found that as TSH values increase—even in the usual normal range—there is
an increased risk for fetal loss.17 Endemic iodine deficiency is the most common cause
Fig. 2. Factors affecting demand for thyroid hormone in pregnancy.
Endocrine Basis for Recurrent Pregnancy Loss
Box 2
Adverse pregnancy outcomes of hypothyroidism
Mother
Infertility
Miscarriage
Anemia
Preeclampsia
Abruptio placenta
Baby
Fetal death
Preterm birth
Low birth weight
Impaired neurocognitive development
of hypothyroidism seen in pregnant women worldwide. Other causes include postsurgical, postradioiodine ablation and hypothyroidism secondary to pituitary disease
such as lymphocytic hypophysitis. However, by far, the predominant etiology of hypothyroidism in iodine-replete populations is the spectrum of chronic autoimmune thyroid disease, often undiagnosed for years before presentation (Box 3). Among
pregnant women, autoimmune thyroid disease has a prevalence of 5% to 20%
depending on the population studied.18 Women with antithyroid antibodies (ATA) during pregnancy have shown that, despite the expected decrease in antibody titers
during gestation, thyroid function gradually deteriorated toward hypothyroidism in a
significant fraction.19 The most commonly targeted thyroid antigens are thyroperoxidase (TPO) and thyroglobulin (Tg), both integral to the production of T4 and T3. The
reported prevalence of anti-TPO and anti-Tg antibodies in asymptomatic women is
14.6% and 13.8%, respectively.20
Stagnaro-Green and colleagues21 first reported an association of ATA with RPL
observing a doubling of the spontaneous miscarriage rate (17.0 vs 8.4%; P 5 .001)
Box 3
Autoimmune thyroid disease during pregnancy and the postpartum period
Asymptomatic autoimmune disease
ATA positive; euthyroid
Subclinical hypothyroidism
Primary hypothyroidism
Hashimoto’s disease
TSH receptor–blocking antibody
Grave’s disease
Euthyroid
Hyperthyroid
Postpartum thyroiditis
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in women with a TSH between 2.5 and 5.0 mIU/L who were ATA positive compared
with an ATA-negative cohort. A pooled analysis of 21 studies (13 cohort and 8 case
control) found an odds ratio (OR) of 2.55 (95% CI, 1.42–4.57; P 5 .002) for recurrent
losses in women with ATA.22 Similarly, a recent meta-analysis found a positive association of ATA with spontaneous pregnancy loss in both cohort (OR, 3.9; 95% CI,
2.48–6.12; P<.001) and case-control (OR, 1.8; 95% CI, 1.25–2.6; P 5 .002) studies.23
The precise pathogenetic link between ATA and pregnancy loss is unknown, and the
association does not imply a causal relationship. Autoimmune thyroid disease may
impair thyroid reserve to such an extent that the gland is unable to respond to the challenge of pregnancy. ATA may be associated with inappropriately low levels of thyroid
hormones for the given gestational period, despite apparent biologic euthyroidism.
Alternatively, autoimmune thyroid disease could act by delaying the occurrence of
conception because of its known association with infertility. Similarly, women with
autoimmune thyroid disease are generally older than healthy controls, and increased
age is an independent risk factor for miscarriage. Finally, ATA may merely be a marker
for a generalized immune imbalance, which may independently promote pregnancy
loss.18,24
Regardless of the causal relationship, there is evidence that thyroid hormone replacement with levothyroxine in pregnant women with hypothyroidism
(TSH >2.5 mIU/L), will improve pregnancy outcome.15,25,26 Furthermore, a Cochrane
study suggested a significant reduction in preterm birth and a trend toward reduced
miscarriage when levothyroxine was used in euthyroid pregnant women with ATA.27
Given that thyroid autoimmunity may be present for many years before the onset of
hypothyroidism, it seems reasonable to test RPL patients for ATA (both anti-TPO
and anti-Tg), preferably immediately before conception.5 For those with positive antibodies and a TSH level greater than 2.5 mIU/L, levothyroxine therapy tailored to the
TSH level is indicated.26 Close monitoring, particularly in the first trimester, is important because of increasing thyroid demands with dosage often requiring titration upward during pregnancy.28 There are no clear recommendations in ATA-positive
pregnancies with a normal TSH (TSH <2.5 mIU/L), but common sense dictates that
at the very least, close follow-up during pregnancy is warranted.
POLYCYSTIC OVARY SYNDROME
Although the exact prevalence is uncertain, women with polycystic ovarian syndrome
(PCOS), have an increased frequency of pregnancy loss.29 In the past, diagnostic
criteria for this heterogeneous disorder have not been uniform, resulting in a wide
range of reported prevalence of both miscarriage and RPL in PCOS patients.30,31 In
2003, a consensus conference reached agreement on what has become known as
the Rotterdam Criteria comprising oligo- or anovulation, hyperandrogenism, and ultrasonographic evidence of polycystic ovaries. PCOS is diagnosed with 2 of 3 defined
criteria satisfied.32 Notably absent from the consensus criteria is any reference to
obesity or insulin sensitivity.
In the past, hypersecretion of LH and androgens have been linked to RPL.33 Early
observations have indicated an association between miscarriage and the elevated
serum LH exhibited by many PCOS patients. However, there was no difference in subsequent pregnancy outcome in RPL women with high LH compared with those with
normal LH.33,34 Furthermore, there was no benefit seen in suppressing LH levels in
PCOS patients with RPL.35 Hyperandrogenism is considered by many investigators
as the essential endocrinologic feature of PCOS. However, the association between
excess androgens and the risk of RPL is also unclear. There was no observable
Endocrine Basis for Recurrent Pregnancy Loss
difference in total testosterone values between women who miscarried and those with
live birth.34 Rai and colleagues33 were unable to show that elevated testosterone
levels in PCOS subjects were associated with an increased miscarriage rate. In
contrast, Mulders and colleagues36 and van Wely and colleagues37 observed that
lower total testosterone and a lower free androgen index in non-RPL women were
more likely to have a successful pregnancy after ovulation induction.
A meta-analysis of 16 studies concluded that women with an increased body mass
index have a significantly increased risk of miscarriage.38 A body mass index greater
than 30 kg/m2 increases the chance of miscarriage by 20% and more than triples the
risk of RPL development.39 Many suffering from PCOS are obese and commonly
found to exhibit metabolic disturbance involving insulin sensitivity. Hyperinsulinemia
as a consequence of insulin resistance, an integral pathogenetic feature of PCOS,
has emerged as a key factor behind the link between PCOS/obesity and the risk of
RPL. Insulin resistance was found to be a significant independent risk factor for
miscarriage in a study that investigated the fasting serum insulin concentrations
before conception in 72 women with PCOS taking metformin.40 Craig and colleagues41 have observed increased insulin resistance in 27% of women with unexplained RPL and have recommended a determination of insulin metabolism as part
of the evaluation of RPL. The connection between obesity and hyperinsulinemia
with miscarriage may involve plasminogen activator inhibitor-1 (PAI-1), which inhibits
plasmin formation during plasminogen activation and subsequent fibrinolysis.
Elevated PAI-1 is reported to be an independent risk factor for pregnancy loss, potentially through a thrombophilic effect.42–44
In observational studies, the use of insulin-sensitizing agents such as metformin has
reduced pregnancy loss in infertile, PCOS women with RPL when used before and
throughout pregnancy.29,45,46 In contrast, a randomized, placebo-controlled trial of
metformin in infertile women did not find any benefit in preventing spontaneous pregnancy loss, but metformin was discontinued with the diagnosis of pregnancy.47 It is
still unclear if benefit could have been found if metformin was continued. Metformin
has shown benefit in reducing the risk of miscarriage in women with a history of
RPL and an abnormal glucose tolerance test result.48 There is significant overlap
among women with PCOS and type II diabetes mellitus. Uncontrolled type II diabetes
is associated with an increased risk of pregnancy loss.49 In a large, controlled, prospective study, early pregnancy loss was significantly correlated with elevated fasting
glucose and glycosylated hemoglobin levels in the first trimester in insulin-dependent
diabetics.50 Metformin use during pregnancy does not appear to have any deleterious
effects among exposed children studied during their first 18 months of life.51 Of
course, the alternative of losing weight in obese, anovulatory patients is also effective
in improving insulin sensitivity and appears to improve fertility and pregnancy
outcome.52
SUMMARY
Common endocrinopathies are a major contributor to both spontaneous and recurrent
miscarriage. Although the diagnostic criteria for LPD are still controversial, treatment
of patients with both RPL and LPD using progestogen in early pregnancy seems beneficial. Hyperprolactinemia, a unique cause of LPD, is easily evaluated and managed.
An increase in thyroid gland function is critical in the maintenance of early pregnancy.
Overt or subclinical hypothyroidism along with the presence of antithyroid antibodies
is correlated with poor obstetric outcome. Thyroid hormone replacement therapy
along with careful monitoring in the preconceptual and early pregnancy period is
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associated with improved outcome. Women with polycystic ovary syndrome, the most
common endocrinopathy of reproductive age women, have an increased risk of pregnancy loss. The precise mechanism is unclear but likely involves hyperinsulinemia, a
common feature of PCOS, possibly acting through the clotting factor PAI-1. Management of PCOS with normalization of weight or metformin seems to reduce the risk of
pregnancy loss.
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27. Reid SM, Middleton P, Cossich MC, et al. Interventions for clinical and subclinical hypothyroidism pre-pregnancy and during pregnancy. Cochrane Database
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28. Mandel SJ, Larsen PR, Seely EW, et al. Increased need for thyroxine during pregnancy in women with primary hypothyroidism. N Engl J Med 1990;323(2):91–6.
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32. Rotterdam ESHRE/ASRM-Sponsored PCOS Consensus Workshop Group.
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33. Rai R, Backos M, Rushworth F, et al. Polycystic ovaries and recurrent miscarriage - a reappraisal. Humanit Rep 2000;15:612–5.
34. Nardo LG, Rai R, Backos M, et al. High serum luteinizing hormone and testosterone concentrations do not predict pregnancy outcome in women with recurrent miscarriage. Fertil Steril 2002;77:348–52.
35. Clifford K, Rai R, Watson H, et al. Does suppressing luteinising hormone secretion reduce the miscarriage rate? Results of a randomised controlled trial. BMJ
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39. Lashen H, Fear K, Sturdee DW. Obesity is associated with increased risk of firsttrimester and recurrent miscarriage: matched case-control study. Humanit Rep
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40. Maryam K, Bouzari Z, Basirat Z, et al. The comparison of insulin resistance frequency in patients with recurrent early pregnancy loss to normal individuals.
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41. Craig LB, Ke RW, Kutteh WH. Increased prevalence of insulin resistance in
women with a history of recurrent pregnancy loss. Fertil Steril 2002;78:487–90.
42. Atiomo WU, Bates SA, Condon JE, et al. The plasminogen activator inhibitor system in women with polycystic ovary syndrome. Fertil Steril 1998;69(2):236–41.
43. Glueck CJ, Wang P, Bornovali S, et al. Polycystic ovary syndrome, the G1691A
factor V Leiden mutation, and plasminogen activator inhibitor activity: assocaition with recurrent pregancy loss. Metabolism 2003;52(12):1627–32.
44. Sun L, Lv H, Wei W, et al. Angiotensin-converting enzyme D/I and plasminogen
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45. Glueck CJ, Phillips H, Cameron D, et al. Continuing metformin throughout pregnancy in women with polycystic ovary syndrome appears to safely reduce firsttrimester spontaneous abortion: a pilot study. Fertil Steril 2001;75(1):46–52.
46. Jakubowicz DJ, Iuorno MJ, Jakubowicz S, et al. Effects of metformin on early
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47. Legro RS, Barnhart HX, Schlaff WD, et al. Cooperative multicenter reproductive
medicine network. Clomiphene, metformin or both for infertility in the polycystic
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48. Zolghadri J, Tavana Z, Kazerooni T, et al. Relationship between abnormal
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Antiphospholipid Antibody
S y n d ro m e
William H. Kutteh,
MD, PhD, HCLD
a,b,
*, Candace D. Hinote,
MD
c
KEYWORDS
Antiphospholipid syndrome Antiphospholipid antibodies
Recurrent pregnancy loss Fetal demise Unfractionated heparin
Complications of pregnancy
KEY POINTS
Antiphospholipid antibodies (aPLs) are acquired antibodies directed against negatively
charged phospholipids, a group of inner and outer cell membrane antigens found in
mammals.
Obstetric antiphospholipid antibody syndrome (APS) is diagnosed in the presence of
certain clinical features in conjunction with positive laboratory findings.
Although obstetric APS was originally reported in association with slow progressive thrombosis and infarction in the placenta, it is most often associated with a poor obstetric outcome.
Several pathophysiologic mechanisms of action of aPLs have been described.
The most common histopathologic finding in early pregnancy loss has been defective endovascular decidual trophoblastic invasion.
Treatment with heparin and aspirin is emerging as the therapy of choice, with approximately 75% of treated women with RPL and aPL having a successful delivery, compared
with less than 30% without treatment.
INTRODUCTION
Antiphospholipid antibodies (aPLs) are acquired antibodies (immunoglobulin [Ig] G,
IgM, and/or IgA isotypes) that react against negatively charged phospholipids.
They were originally associated with a slow progressive thrombosis and infarction
in the placenta1 and thus have been classified as thrombophilic factors. aPLs should
additionally be classified as autoimmune factors when considering implantation and
The authors have nothing to disclose.
a
Department of Obstetrics and Gynecology, Vanderbilt University Medical Center, Nashville,
TN, USA; b Fertility Associates of Memphis, PLLC, 80 Humphreys Center, Suite 307, Memphis, TN
38120, USA; c MidSouth OB GYN, 6215 Humphreys Boulevard, Suite 100, Memphis, TN 38120, USA
* Corresponding author. Fertility Associates of Memphis, PLLC, 80 Humphreys Center, Suite 307,
Memphis, TN 38120.
E-mail address: wkutteh@fertilitymem.com
Obstet Gynecol Clin N Am 41 (2014) 113–132
http://dx.doi.org/10.1016/j.ogc.2013.10.004
obgyn.theclinics.com
0889-8545/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
114
Kutteh & Hinote
pregnancy because of the complex nature of the interaction of aPLs with target tissues. They have been shown to inhibit the release of human chorionic gonadotropin
from human placental explants; to block in vitro trophoblast migration, invasion,
and multinucleated cell formation; inhibit trophoblast cell adhesion molecules;
and to activate complement on the trophoblast surface, inducing an inflammatory
response.2–5
Antiphospholipid syndrome (APS) is an autoimmune condition characterized by the
production of aPL combined with certain clinical features. The presence of aPL
(including anticardiolipin [aCL] and lupus anticoagulant [LAC]) during pregnancy is a
major risk factor for adverse pregnancy outcome.6 In large meta-analyses of studies
of couples with recurrent pregnancy loss (RPL), the incidence of APS was between
15% and 20% compared with about 5% in nonpregnant women without a history of
obstetric complications.7,8 It is not yet understood how aPLs arise in patients with
APS. Genetic factors and infection may play a role. Family studies suggest a genetic
disposition to APS, either when it presents as a primary condition or when it is seen in
the context of systemic lupus erythematosus (SLE). This genetic disposition is
accounted for, at least in part, by the major histocompatibility complex. The antibodies
generated in patients with APS seem to recognize epitopes on phospholipid-binding
proteins, unlike the antibodies that arise following infections such as syphilis and Lyme
disease, which recognize phospholipids directly.9
DIAGNOSIS OF APS
APS is a syndrome that is defined based on both clinical and laboratory criteria. The
diagnosis can be based on the presence of the clinical manifestation together with the
laboratory detection of abnormal antibodies (Box 1). APS is designated as primary in
patients without clinical or laboratory evidence of an underlying condition or disease,
and secondary when it is associated with other diseases or conditions.10 SLE is the
disorder in which APS is most commonly associated but it may be associated with
other conditions.11,12 Box 2 lists the conditions associated with secondary APS that
may be relevant to obstetricians.
Widespread interest in APS among all areas of medicine led to the First International Symposium on Antiphospholipid Antibodies in 1984. The purpose of this group
was to bring together the international research and clinical communities with the
goal of clinical and scientific sharing and standardization of APS. Meetings have
been held periodically with research and clinical data reviewed and discussed at preconference meetings and committees. An article was published with the latest suggested criteria for the diagnosis of APS with the current version referred to as the
Sydney criteria.13 These criteria should be useful for research investigations because
the criteria result in specific diagnoses; however, in the clinical setting, these criteria
are not very sensitive. These committee recommendations have been widely published, but the committee is not sanctioned or supported by any governing body
such as the American College of Obstetricians and Gynecologists. The committee
is primarily composed of rheumatologists, hematologists, and internists, with minor
representation from obstetricians.
Clinical Criteria
The clinical manifestations of primary and secondary APS are diverse and may involve
most organ systems.10,14 Based on currently available evidence, vaso-occlusive disease is the pathologic basis for many of the complications of primary and secondary
APS. Therefore, preconception counseling of the patient with APS regarding the risks
Antiphospholipid Antibody Syndrome
Box 1
Clinical and laboratory criteria established for the research of definite antiphospholipid
syndrome: the Sydney criteria
Note: At least 1 clinical and 1 laboratory criterion must be present for definite APS.
Clinical criteria
1. Vascular thrombosis
One or more clinical episodes of an arterial, venous, or small vessel thrombosis, confirmed
by imaging or Doppler studies or histopathology, without significant evidence of
inflammation in the vessel wall.
2. Obstetric morbidity
a. One or more unexplained demise of a morphologically normal fetus at or beyond
10 weeks of gestation, or
b. One or more premature births of a morphologically normal neonate at or before
34 weeks of gestation, caused by severe preeclampsia or severe placental insufficiency, or
c. At least 3 unexplained, consecutive miscarriages of less than 10 weeks of gestation.
Known factors associated with recurrent miscarriage, including parental genetic,
anatomic, and endocrinologic factors, should be ruled out.
Laboratory criteria
1. aCL IgG and/or IgM in blood, present in medium or high titers (greater than 40 GPL or MPL
or greater than the 99th percentile) on 2 or more occasions at least 12 weeks apart,
measured by a standardized ELISA.
2. Anti-b2GP1 antibody of IgG and/or IgM isotype in blood (greater than the 99th percentile)
on 2 or more occasions at least 12 weeks apart, measured by a standardized ELISA.
3. Lupus anticoagulant present in plasma, on 2 or more occasions at least 12 weeks apart,
detected according to the guidelines of the International Society on Thrombosis and
Hemostasis, which include the following steps:
a. Prolonged phospholipid-dependent coagulation using a screening test such as the aPTT,
kaolin clotting time, dilute Russell viper venom time, and dilute prothrombin time
b. Failure to correct the prolonged coagulation time on the screening test by mixing with
normal plasma
c. Shortening or correction of the prolonged coagulation time on the screening test by the
addition of excess phospholipid or platelets
d. Exclusion of other coagulopathies (eg, factor VIII inhibitor) or heparin
Adapted from Werner E, Lockwood C. Thrombophilias and Stillbirth. Clin Obstet Gynecol
2010;53:617–27; with permission.
for serious medical problems is essential. In women referred to reproductive endocrinologists with APS and histories of early loss, the prevalence of prior thromboembolic
events is low. However, these patients are still at risk for thromboembolic events.
Estrogen-containing oral contraceptive pills should be avoided in women with
repeated positive aPL.15 Furthermore, women should be counseled that a single
low-dose aspirin (81 mg) per day may decrease this future risk for thromboembolic
event, as suggested by Silver and colleagues.16 Thus, it is important for clinicians to
be cognizant of the red flags, which are indications to perform diagnostic testing for
the LAC and aCL antibodies (Box 3).
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Box 2
Classification of the APS relevant to obstetricians
I. Primary APS
Obstetric antiphospholipid syndrome
II. Secondary APS
A. Autoimmune disease
SLE
Rheumatoid arthritis
Sjögren syndrome
Systemic sclerosis
Diabetes mellitus
Crohn disease
Autoimmune thyroid disease
B. Malignancies
Carcinoma of ovary and cervix
Lymphoma
Leukemia
C. Drug-induced conditions
Oral contraceptives
D. Infectious diseases
Syphilis
Human immunodeficiency virus infection
Box 3
Indications to identify LAC and aPL in obstetric patients
RPL
Unexplained second-trimester or third-trimester loss
Fetal demise
Early-onset, severe preeclampsia
Pregnancy-related thrombosis (venous or arterial)
Severe IUGR
Autoimmune or connective tissue disease
False-positive serologic test for syphilis (Venereal Disease Research Laboratory or rapid plasma
reagin)
Prolonged coagulation studies
Positive autoantibody tests
Antiphospholipid Antibody Syndrome
Laboratory Criteria
Lupus anticoagulant is an immunoglobulin (usually IgG, IgM, or both) that interferes
with one or more of the phospholipid-dependent tests of in vitro coagulation.17 The
name is a misnomer in 2 ways. Although it is called an anticoagulant, patients with
LAC more frequently have a hypercoagulable state. Second, LAC is frequently
found in patients without SLE. The most common tests that have been used to identify the LAC include the activated partial thromboplastin time (aPTT), the kaolin clot
time (KCT), the dilute Russell viper venom time (dRVVT), and the plasma clot time
(PCT).
The advantages, disadvantages, and sensitivity of the screening procedures used
for LAC are listed in Table 1. aPTT reagents vary widely in their sensitivity to LAC
because of variations in the phospholipid present in the reagent. It is not a reliable
test to use in pregnancy because coagulation proteins, which increase during pregnancy (fibrinogen, factor VIII, von Willebrand factor, factor VII, and factor X), may
mask the LAC. The KCT is reliable and sensitive but cannot be used as a confirming
test. The dRVVT is a sensitive test and, because the snake venom activates factor X,
this test is less affected by pregnancy.18
Regardless of which test is used, there are 3 steps that are necessary to identify
an LAC. Once a prolonged in vitro coagulation test has been identified, it is necessary
to document the presence of an inhibitor. Most commonly, mixing studies are
done with pooled normal platelet-poor plasma and patient plasma in a 1:1 ratio. In
general, a marked prolonged aPTT corrects to nearly the value of normal plasma (within
5 seconds) if the abnormal coagulation test was caused by a factor deficiency. To
confirm that the persistently prolonged aPTT is caused by the LAC, a confirmatory
test, such as the platelet neutralization test, must be performed. Frozen, thawed
Table 1
Screening tests for lupus anticoagulants
Test
Variables Affected
by Pregnancy
Advantages
Disadvantages
Sensitivity
aPTT
Increased factor VIII
may mask
Readily available,
easily automated,
can be used in PL
confirmatory step
Reagents vary
widely in
sensitivity to LAC
Least
KCT
Not significantly
affected by
pregnancy
Very sensitive to LAC
if patient is on oral
anticoagulants
Very sensitive to
residual platelets;
not readily
automated; cannot
use in PL
confirmation step
Most
dRVVT
Not significantly
affected by
pregnancy
Easy to perform;
readily available
Manual techniques,
affected by
heparin or oral
contraceptives
Good
PCT
Increased factor VII
may blunt LAC
effect
Requires no reagents
or equipment
Must be performed
on freshly drawn
blood; manual
technique
Good
Adapted from Branch DW, Silver RM, Blackwell JL, et al. Outcome of treated pregnancies in
women with antiphospholipid syndrome: an update of the Utah experience. Obstet Gynecol
1992;80:614–20; with permission.
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platelets contain and release excess phospholipid, which is added to the patient
plasma. The LAC is absorbed to the phospholipid and the in vitro coagulation test
returns toward normal.17
aPLs are acquired antibodies (IgG, IgM, and/or IgA) that belong to the large family
of antibodies that react against negatively charged phospholipids, including cardiolipin (diphosphatidyl glycerol), phosphatidylserine, phosphatidylinositol, and phosphatidylglycerol. In 1983, Harris introduced a solid phase immunoassay for cardiolipin.19
Two years later, he developed an enzyme-linked immunosorbent assay (ELISA) for
cardiolipin, which remains the gold standard. In this immunoassay, cardiolipin, phosphatidylserine, and other phospholipids are used as coating antigens on microtiter
plates. There have been 3 international workshops to standardize reporting. Standards for cardiolipin IgG, IgM, and IgA are commercially available through the Antiphospholipid Laboratory, Inc. These standard sera have been assigned numerical
values based on their ability to bind 1 mg of cardiolipin and the units are reported as
IgG phospholipid units (GPL). Based on the original studies and recommendations
of Harris,7 positive values are considered greater than or equal to 20 GPL, greater
than or equal to 20 IgM phospholipid units (MPL), and greater than or equal to 30
IgA phospholipid units (APL), respectively. It has been recommended that values be
reported in a semiquantitated fashion such as negative, borderline, positive, and
high positive. Positive tests should ideally be confirmed in 6 to 8 weeks. In general,
aPLs decline during pregnancy, perhaps because of increase maternal blood volume
and dilution. However, aPLs may increase in as many as 20% of women during
pregnancy.
A major target molecule for aPL binding seems to be beta-2 glycoprotein-1 (b2GP1)
present on the surface of trophoblastic cell membranes.20,21 b2GP1 is a cationic
plasma protein that is bound to phosphatidylserine, which is exposed on the surface
of trophoblastic cell membranes undergoing syncytial formation. Although the physiologic role of b2GP1 is unclear, the molecule seems to inhibit thrombosis by reducing
the conversion of prothrombin to thrombin on platelets and inhibiting the activation of
the intrinsic coagulation cascade.22 b2GP1 was added to the criteria for the definitive
diagnosis of APS in the Sydney criteria13; it is thought to be a more specific indicator of
APS but several studies indicate that it is less sensitive than aCL or aPL for the diagnosis of APS.
OBSTETRIC COMPLICATIONS OF APS
Determining the diagnosis of APS in an individual patient requires both laboratory and
clinical criteria to be met. The most recent compelling data for a link between aPLs and
pregnancy complications come from studies in women with recurrent miscarriage,23,24
although data associated with fetal loss, severe preeclampsia before 34 weeks’ gestation, and severe placental insufficiency are also increasing.25
Recurrent Pregnancy Loss
RPL has been defined as 2 or 3 or more consecutive losses before the 20th week of
gestation with the same partner, and affects up to 2% to 4% of pregnancies.26,27 However, requiring 3 failed pregnancies before initiating a work-up may offer little additional clinical insight compared with testing after the second loss.27,28 The risk of
miscarriage in subsequent pregnancies is 30% after 2 losses and 45% after 3 losses
in patients without a history of live birth, therefore testing after 2 consecutive losses
may spare the affected couple the difficulty of dealing with an additional failed pregnancy, and may minimize excessive and unproductive evaluation. The American
Antiphospholipid Antibody Syndrome
Society of Reproductive Medicine recently defined RPL as 2 or more failed clinical
pregnancies as documented by ultrasonography or histopathologic documentation
of products of conception to address this point, and recommended a thorough evaluation of RPL after two or more clinical losses.27 It has been observed that circulating
aPLs is the main risk factor in 7% to 25% of early RPL (loss in the first trimester),
whereas prevalence studies show that between 1% and 5% of patients have
LAC.29,30 The failure rate of pregnancies when APS is strictly defined as aPL levels
of greater than the 99% of a normal population is estimated to be up to 90% (52%
of early miscarriages and 38% of late fetal loss). Patients positive for aPL with a first
unexplained pregnancy loss before the 10th week of gestation are likely to experience
a high-risk second pregnancy.31 Although all 3 of the laboratory criteria for diagnosis
of APS (the presence of LAC, increased levels of aCL antibodies, and increased levels
of b2GP113) have been linked with RPL, the risk varies with the different types of antibodies. For example, the presence of aCL antibodies is associated with an odds ratio
(OR) of 22.6 (95% confidence interval, 5.7–8.9) for subsequent pregnancy loss, and
the presence of b2GP1 antibodies increases the chance of recurrent miscarriage
from 6.8% to 22.2% compared with women with LAC or aCL.32
As the literature confirmed the strong association between aPL antibodies and RPL,
and as a better understanding of the pathogenic concepts of APS and fetal loss have
been reported,33 the obvious results have been attempts to use this knowledge to
develop therapies for this common complication of pregnancy. Although low-dose
aspirin plus heparin has been shown to reduce pregnancy loss rates in patients with
RPL, the optimal dose and regimen continue to be investigated as recent reports indicate.34,35 Based on these recent studies, it is becoming clear that, although live birth
rates are improving with therapy, older studies suggest that these patients are still at
risk for late pregnancy complications including stillbirth, early-onset preeclampsia,
and intrauterine growth restriction (IUGR).36,37
Fetal loss
Late fetal loss (after 10 weeks of pregnancy) associated with aPL antibodies is one of
the diagnostic criteria for APS,13 with aCL antibodies and b2GP1 antibodies, but not
LAC, being strongly associated with intrauterine fetal death.32,38,39 Late fetal loss is
also more common as the number of aPL antibody tests become positive. In a recent
report from Italy involving 97 pregnancies in 79 patients with APS and without
hereditary thrombophilia, triple positivity conferred a risk of late fetal loss of 52.6%
compared with a loss rate of 2.2% when only 2 tests were positive.40 This observation
again highlights the potential importance of other aPLs as a part of the diagnostic evaluation for RPL.
Information regarding the association between APS and stillbirth (defined as an
intrauterine fetal death at a minimum gestational age of 20 weeks) is less well defined,
and only a few articles have specifically commented on APS and stillbirth. Therapy for
patients with a prior stillbirth and APS with low-dose aspirin and heparin is commonly
used but not supported by large-scale randomized controlled trials.41
Severe preeclampsia before 34 weeks
Another clinical criterion that defines APS is a preterm birth resulting from severe
preeclampsia at or before 34 weeks of gestation, and different methodologies have
been used to document this association. When using the International Classification
of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code for the aPL syndrome (795.79) in a hospital discharge dataset to investigate the presence of APS in
a large (141,286) group of women who delivered in Florida in 2001, APS had an
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increased adjusted OR for preeclampsia and eclampsia at any gestational age of 2.93
(95% confidence interval, 1.51–5.69).42 A systematic review and meta-analysis of 64
full-text studies that yielded 12 studies for analysis concluded in 2010 that the pooled
OR for the association of aCL antibodies alone with preeclampsia was 2.86 (95% confidence interval, 1.37–5.98), and for severe preeclampsia (95% confidence interval,
2.66–46.75) was 11.15.43
This study again reported preeclampsia at all gestational ages and made no recommendations regarding screening for aCL antibodies in the presence of preeclampsia.
A recent review in 2011 of APS and preeclampsia reported a rate of 20% of patients
with severe preeclampsia before 34 weeks having at least 1 aPL test positive
compared with 6% in late-onset (after 34 weeks’ gestation) preeclampsia.44 These
results compare favorably with controlled cohort studies reviewed in that article,
and the investigators conclude that, in the patient with severe preeclampsia at less
than 34 weeks’ gestation, testing should be done for LAC, aCL antibodies, and
b2GP1 antibodies. Reinforcing the concern expressed earlier, Branch and colleagues45 observed that 50% of women with APS develop preeclampsia despite treatment of early-onset pregnancy complications. In the past, many of these patients were
treated with steroids, which have been shown to increase the frequency of gestational
hypertension, gestational diabetes, and preterm delivery.46,47 More recent studies that
used heparin for the treatment of women with APS have not reported the same high
frequency of late pregnancy complications.34,35,48,49
Severe Placental Insufficiency
Severe placental insufficiency, another clinical criterion of the APS, is the least
well-defined criterion, and usually includes IUGR and abruptio placenta at or before
34 weeks’ gestation. Using the 2001 Florida dataset described earlier, placental insufficiency (as defined by ICD-9-CM codes) presented an adjusted OR of an association with APS of 4.58 (95% confidence interval, 2.00–10.51).42 Older studies reported
IUGR to occur in approximately one-third of patients diagnosed with APS,45,50 and
aCL antibodies are significantly associated with IUGR as well.38,51 Because IUGR
is most commonly seen in the presence of preeclampsia, causality is difficult to
establish.
Although there are no prospective trials studying the association between abruptio
placenta and APS, Alfirevic and colleagues39 noted an association between abruptio
and aCL IgG antibodies in a systematic review in 2002.
Obstetric complications abound in the presence of APS, but therapeutic recommendations are either incomplete or inadequate. However, results from European
registries of infants born to mothers with APS seem to fare well with no cases of
neonatal thrombosis52 and rare long-term complications. It is hoped that advances
in understanding of the pathophysiology of APS will lead to more successful management schemes and therapy.
PATHOPHYSIOLOGY OF APS
The diagnosis of APS requires both the presence of aPL and specific clinical manifestations, including RPL, fetal demise, and obstetric complications such as preeclampsia and IUGR. The presence of aPL is the most common autoimmune risk factor for a
treatable cause of RPL, fetal demise, and early, severe preeclampsia.53,54 The presence of aPL is not simply diagnostic in obstetric APS, it is also pathogenic. Animal
studies have indicated that the passive transfer of aPL promotes fetal loss and
placental thrombosis, and also inhibits trophoblast and decidual cell functions
Antiphospholipid Antibody Syndrome
in vitro.55–57 Cross-species investigations have shown that the exposure of pregnant
rats to a purified IgG fraction from women with APS directly inhibits embryo growth.58
Histologic studies on the placentas from aPL-treated mice showed thrombotic lesions
of decidua basalis maternal blood vessels and necrosis of the placental tissues. aPLs
interact with phospholipid-binding plasma proteins to cause arterial and/or venous
thrombosis in the absence of other conditions that promote blood coagulation. The
two most clinically relevant phospholipid-binding proteins that react with aPL autoantibodies are b2GP1 and prothrombin.53 aPLs impair fetal growth and development via
mechanisms of thrombosis, inhibition of normal placentation, and local inflammatory
destruction.
Thrombosis and aPLs
The primary hypothesis for the major pathogenic mechanism for aPL-induced pregnancy loss and fetal growth restriction is placental thrombosis. Thrombosis of vessels
causes placental infarction with resultant impairment of maternal-fetal nutrient and
oxygen exchange. This hypothesis is supported by the finding of thrombosis and
infarction in the placentas of women with APS who had miscarriages in the first
and second trimesters.1,59,60 The scientific plausibility for placental thrombosis as a
cause of obstetric complications in APS is supported by the evidence that increasing
aCL titers are correlated with an increased risk of peripheral thrombosis.61,62 The
presence of LAC seems to cause a higher risk of thrombosis than aCL.63 IgG from
the sera of LAC-positive patients increased thromboxane synthesis in placental
explants compared with controls. This relative increase in thromboxane activity
would produce a thrombophilic state.64 Other studies have indicated that aPL could
promote thrombosis by interfering with protein C activation65 and diminishing antithrombin activity.66
A major target molecule for aPL binding seems to be b2GP1, which is present on
the surface of trophoblastic cell membranes.20,21 b2GP1 is a cationic plasma protein
that is bound to phosphatidylserine (PS), which is exposed on the surface of trophoblastic cell membranes undergoing syncytial formation. Although the physiologic
role of b2GP1 is unclear, the molecule seems to inhibit thrombosis by reducing the
conversion of prothrombin to thrombin on platelets and inhibiting the activation of
the intrinsic coagulation cascade.22 Polyclonal IgG from the sera of patients with
APS binds to b2GP1 on trophoblastic cells in culture with potential thrombogenic
consequences.3,67 However, observations in murine models and humans are not
consistent with the obligate involvement of b2GP1 as a natural inhibitor of placental
thrombosis in APS. Mice deficient in b2GP1 have smaller litter sizes and placental
insufficiency but otherwise have similar reproductive outcomes compared with control
mice.68 In addition, individuals have been identified who are deficient in b2GP1 but do
not show the clinical signs of APS.69
Another mechanism for aPL-mediated thrombosis may involve a disruption of the
normal function of a plasma protein called annexin V.70 The binding of cationic annexin
V molecules to the anionic PL molecules on the surface of the trophoblastic membrane
seems to prevent thrombosis by forming a protective protein coat. This protective
coat might prevent the activation of the clotting cascade by blocking the binding of
activated factor X and prothrombin. In vitro studies indicate that aPL could displace
annexin V from the surface of endothelial and trophoblastic cells in culture, thus
activating the clotting cascade. This mechanism is supported by the finding that
women with aPLs have diminished annexin V binding to the surface of trophoblastic
cells of the intervillous space compared with controls.71
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Mechanisms besides placental vascular thrombosis are likely to play a role in the
RPL and pregnancy complications associated with obstetric APS. Histopathologic
studies have not always confirmed thrombosis in the placentas from women with obstetric APS.7,72,73 Meta-analyses examining the association of aPLs with placental
thrombosis have evaluated index women with systemic thrombosis who were subsequently tested for aPLs, potentially introducing selection bias into these investigations.
There have been no large prospective studies of unselected patients whose aPL
status was determined before objective documentation of thrombotic complications.
As a result, the temporal association between aPLs and the subsequent development
of placental thrombosis has not been definitively documented.74
Defective Placentation
Abnormalities of early trophoblast invasion caused by aPLs are a likely pathogenic
mechanism in obstetric APS.75 Experimental models indicate that aPLs can directly
retard trophoblast invasiveness, impair trophoblastic cellular differentiation and
maturation, and diminish human chorionic gonadotropin secretion.3,76 The histologic
abnormality most frequently observed in APS-associated early pregnancy loss was
defective decidual endovascular trophoblast invasion, rather than intervillous thrombosis. Exposure of trophoblastic cell monolayers to aPLs resulted in an increased
rate of programmed cell death (apoptosis) and inhibition of syncytial formation.58,77
The sequential expression of cell adhesion molecules between trophoblastic and
decidual cells is involved in trophoblastic invasion during normal placentation. Using
an in vitro model of trophoblast invasion, it was recently reported that aPLs might
affect placental invasion through an abnormal trophoblastic expression of integrins
and cadherins.78
These findings provide supportive evidence that aPLs may be pathogenic in obstetric APS by directly impairing normal placentation via a mechanism independent of
placental or decidual thrombosis.
Local Inflammatory Events
The maternal immune system is transformed during normal pregnancy to prevent
immune rejection of the fetoplacental unit. Acute inflammatory responses generally
promote adverse pregnancy outcome and chemokine mediators favor a profile of T
helper cells type 2 (Th2) responses in early pregnancy which block acute immune
rejection.45 Complement-mediated immune attack is suppressed in normal pregnancies, resulting in viable delivery by complement inhibitory proteins expressed on
trophoblast cells.79 Studies in mice indicate that inhibition of complement C3 activation and deficiencies of C5 and C5a seem to protect against pregnancy loss and fetal
growth restriction.80,81
The binding of aPL to trophoblast cell membranes promotes complement activation, specifically C3a and C5a, resulting in thrombosis and pregnancy loss.82 Instigators of inflammatory tissue injury caused by complement activation include the
chemokine tumor necrosis factor (TNF) alpha and the cytokine receptor, tissue factor
(TF). Exposure of pregnant mice to aPL causes an increase in decidual TNF-a levels,
putatively secondary to C5 activation.83 In an APS mouse model, antibody-mediated
reduction of TNF-a helped prevent fetal resorption.84 Therefore, TNF-a is a likely mediator that links complement activation and aPL to placental inflammatory injury. Complement activation (C5a–C5aR) increases TF expression in neutrophils, which increase
generation of reactive oxygen species thus providing a novel mechanism to explain
fetal loss.85 An additional mechanism whereby TF could promote placental injury in
APS is its capacity to activate the coagulation pathway, leading to thrombosis.86
Antiphospholipid Antibody Syndrome
More evidence is required to confirm the role of complement-mediated pregnancy
loss in women with APS. Histopathologic studies reveal that placental tissue from APS
gestations show a clustering of inflammatory cells and macrophages around blood
vessels compared with controls.87 Other investigations have not consistently shown
the presence of complement complex deposition in placental tissue from women
with APS.88 Important future work will help determine whether therapy that targets
interruption of complement-mediated inflammatory injury will be effective in improving
pregnancy outcome in women with APS.
Mechanism of Therapeutic Benefit of Heparin
The therapeutic benefit of heparin and aspirin in improving outcomes in women with
obstetric APS has been presumed to relate to their anticoagulant properties. However,
the efficacy of heparin in the management of obstetric APS is achieved at a dosage
lower than is required to achieve clinical anticoagulation. Studies in the murine model
indicate that anticoagulants such as hirudin and fondaparinux are ineffective in the
treatment of aPL-induced pregnancy loss, despite having anticoagulant effects similar
to heparin.89 Several mechanisms have been identified that may explain the beneficial
effects of heparin independently of its anticoagulant action.
Low-molecular-weight heparin (LMWH) directly impedes aPL binding to trophoblast
cells and reinstates normal trophoblast invasiveness and differentiation hindered by
aPL. Heparin also can potentially regulate apoptosis in placental explants by
increasing levels of Bcl-2, an antiapoptotic protein.90 Furthermore, heparins have
been shown to prevent complement activation in vitro, an action that would protect
normal placentation from inflammatory injury. Exposure of trophoblastic cells to
LMWH results in an increase in matrix metalloproteinases in trophoblastic cells, an action that would promote trophoblastic invasiveness.91 Heparin sulfate directly binds
aPL, providing a novel and alternative mechanism for its therapeutic benefit in treating
obstetric APS.92,93
Thus, heparin may prevent pregnancy complications in obstetric APS by inhibiting
the binding of aPL to trophoblastic cell membranes, modulating trophoblast apoptosis,
promoting trophoblast cell invasiveness, and reducing complement activation with
the ensuing inflammatory response at the decidual-placental interface. All of these
mechanisms are independent of heparin’s known anticoagulant property in inhibiting
thrombosis.
MANAGEMENT OF APS IN PREGNANCY
Overview of Proposed Treatments
Only 20% to 30% of patients with LAC and/or positive levels of aPL who have had
unsuccessful previous pregnancies have a successful delivery without treatment.16,47
Comparison of studies in the literature is unsatisfactory because of differences in
study design, patient selection, and treatment regimens. There are few randomized
clinical trials, and variations in study definitions affect tabulated outcomes. Pregnancy
outcomes are not always defined. Women with low levels of aPL are included in some
studies. Moreover, aPL assays performed in laboratories with inappropriate standardization or controls may further complicate interpretation of results.
Several treatments have been proposed, including a single low-dose aspirin per day
(81 mg), aspirin and low-dose or high-dose prednisone, aspirin and unfractionated
heparin, aspirin and LMWH, and intravenous immunoglobulin.94 All treatments seem
to improve the live birth rate; however, the combination of unfractionated heparin
with low-dose aspirin seems to provide the highest success rates.34,35,48,49 Aspirin
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is thought to improve outcome by selective inhibition of thromboxane production thus
restoring the balance with prostaglandin. Concomitant use of prednisone and heparin
is generally not recommended because this combination has not been shown to be
better than either alone and may increase the risk of fractures. In a randomized trial
comparing heparin and aspirin versus prednisone and aspirin, Cowchock and colleagues included a small group of 20 women with at least 2 early losses.46 However,
patients were not assigned to treatment until after the documentation of a fetal heartbeat, thus the outcome that showed that the treatments were equal in achieving a
successful outcome has been questioned. However, treatment with corticosteroids
was associated with increased neonatal morbidity (preterm delivery and low birth
weight) and increased maternal morbidity (pregnancy-induced hypertension and
gestational diabetes). A more recent prospective randomized clinical trial comparing
prednisone and aspirin (100 mg/d) for women with autoantibodies and unexplained
recurrent fetal loss showed no benefit in promoting live birth with prednisone and
aspirin but an increase in prematurity.47
Unfractionated Heparin Compared with LMWH
In our prospective trial of aspirin alone versus aspirin and heparin, a group of wellcharacterized women with APS (3 early RPLs), an otherwise negative evaluation,
and positive aPL on 2 occasions were given different treatments.95 The group treated
with aspirin alone had a 44% live birth rate, whereas the group treated with subcutaneous heparin and aspirin had a 78% live birth rate (P<.05). The incidence of maternal
complications was low and there were no significant differences in the birth weight,
incidence of pregnancy- induced hypertension (PIH), gestational diabetes, or cesarean section.
Low-dose heparin is emerging as the treatment of choice for RPL associated with
antiphospholipid syndrome.15,27,34,39,49,92,95 Heparin treatment is generally initiated at
5000 to 7500 U twice a day when the pregnancy test is positive. It is important to
obtain a baseline platelet count and partial thromboplastin time. Heparin treatment
is associated with heparin-induced osteopenia at total daily doses of more than
15,000 international units (IU) per day which, combined with the normal osteoporosis
associated during pregnancy, can be accompanied by increased bone loss. The heparinized pregnant patient should increase her intake of calcium to 600 mg orally twice
a day along with vitamin D 400 IU twice daily to optimize absorption of calcium and to
reduce the risk of osteopenia (Box 4). Heparin is also reported to be associated with
thrombocytopenia. However, the incidence in populations of patients treated at our
center at daily doses of less than 15,000 IU per day has been less than 1%. During
pregnancy, the normal platelet count is more than 100,000/mL compared with the
nonpregnant state, in which platelet counts are normally more than 150,000/mL. If
counts were normal before conception and decreased dramatically during pregnancy, the heparin dosage should be reduced. It is important to instruct patients carefully on the proper administration of subcutaneous heparin to minimize complications.
We use an intensive one-on-one teaching session with a nurse specialist before
conception and have found that using this type of therapy reduces the stress level
of patients.
The first prospective, randomized trial suggested that low-molecular-weight heparin
may be an effective alternative to unfractionated heparin in the treatment of APS.96 In a
2-centered, nonrandomized study, the use of aspirin 81 mg daily in combination with
LMWH during pregnancy for the prevention of RPL in women with APS seemed to be
as safe as unfractionated heparin plus aspirin.97 Large, randomized trials are required
to determine differences in outcome with LMWH and low-dose aspirin compared with
Antiphospholipid Antibody Syndrome
Box 4
Guidelines for prophylactic heparin plus aspirin treatment of patients with RPL without a
history of thromboembolism but with APS
1. Baseline nonpregnant studies of aPLs, complete blood count with platelets, PT, PTT, and
lupus anticoagulant should be obtained. aPL assay should be confirmed before pregnancy.
2. Aspirin 81 mg should be initiated before conception and discontinued 4 weeks before the
expected delivery date. Aspirin 81 mg should be resumed postpartum and continued for
life unless otherwise contraindicated or until better recommendations are available.
3. Subcutaneous heparin (5000 units every 12 hours) should be initiated when pregnancy is
confirmed unless instructed otherwise. Patients who weigh more than 80 kg (175
pounds) should use heparin 7500 units every 12 hours. Platelets and PTT tests should be
checked every week for 2 weeks initially, 1 week following any adjustment in dose, and
each trimester throughout pregnancy to evaluate for heparin-induced thrombocytopenia
(patients with prior thromboembolic events should be fully anticoagulated).
4. Calcium carbonate (1200–1500 mg) with vitamin D (800–1000 IU) should be taken daily in
divided doses once a patient starts heparin to decrease the bone loss associated with
pregnancy and heparin therapy.
5. The pregnancy should be documented by ultrasonography by 7 weeks for the detection of
fetal heart motion. Further sonography may be performed at 18 to 20 weeks.
6. Antenatal testing should begin at 28 to 30 weeks, based on the possible increased risk of
fetal growth restriction and stillbirth. This testing may include kick counts, nonstress tests,
and/or serial biophysical profiles. Serial scans for growth rate may be indicated.
7. Heparin should be continued until the patient initiates spontaneous labor or until the
night before any scheduled induction or operative delivery. One heparin dose may be
skipped the night before amniocentesis. Heparin should be restarted postpartum at the
lowest predelivery dosage and continued for 4 weeks (in those patients with previous
thromboembolic events, full anticoagulation should continue for 6 weeks postpartum).
8. For prolonged deliveries and operative deliveries, the use of pneumatic sequential
compression devices or hose should be considered until the patient is ambulatory.
9. If the patient is fully anticoagulated and delivery is emergent, 1% protamine sulfate can be
administered intravenously over 10 minutes (2.5 mg protamine per 1000 U heparin,
maximum 50 mg protamine) if coagulation indicators are increased.
10. Patients should not use estrogen-containing birth control pills for contraception. Aspirin
81 mg daily is advised until further recommendations become available. Patients who
smoke should be advised to stop.
Data from Refs.15,49,95
treatment with unfractionated heparin combined with low-dose aspirin in this group of
patients.
Antepartum Surveillance
Antepartum testing has been recommended, based on the increased risk for poor
obstetric outcome. For women who have had only first-trimester losses, it is usual
to perform serial ultrasonic assessments weekly until the patients have progressed
beyond the point of their prior losses. If the patient had a prior second-trimester or
third-trimester fetal loss, serial antepartum testing is recommended.15 Antepartum
assessment using daily fetal kick counts, twice weekly nonstress tests, or weekly
biophysical profile has been suggested.
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POSTPREGNANCY CONSIDERATIONS
Immediately Postpartum
Women who had a vaginal delivery should ambulate as soon as possible. Women who
had a cesarean delivery should continue to use pneumatic compression stockings
until they are fully ambulating. Aspirin 81 mg a day can be reinitiated if not contraindicated for other reasons. Authorities recommend that women should receive thromboprophylaxis postpartum for 4 to 6 weeks.15 In general, this recommendation includes
women with and without a prior history of thrombosis. Supplemental calcium should
be continued as long as the patient is taking heparin. Breast-feeding is not
contraindicated for women taking low-dose aspirin or prophylactic heparin.
Lifelong Consequences of APS
Women with APS have been diagnosed with an acquired autoimmune syndrome
similar to SLE. Once the diagnosis is made with appropriate clinical criteria, this should
be considered to be a diagnosis that they carry for life. For example, an individual with
lupus may have an exacerbation and be severely disabled with multiple abnormal
laboratory tests, but, after resolution, her symptoms and laboratory tests may
normalize. Many physicians are confused when a patient with APS who previously
had positive tests presents years later and the test results have returned to normal;
however, in our opinion the patient should still be considered to have the diagnosis
of APS. As such, we recommend that, once the diagnosis of APS is made, women
should not use estrogen-containing oral contraceptive pills but should use
progestin-only pills, barrier methods, or intrauterine devices.15 They should similarly
not use tobacco products and should maintain a normal weight. Any correctable
risk factors for future thrombosis, such as increased cholesterol, should also be
corrected. We agree with the recommendation that these women should use lifelong
aspirin 81 mg per day unless it is contraindicated for other reasons.98 In general, these
individuals should live a healthy lifestyle.
SUMMARY
It is unclear at this time what treatment, if any, is required for women who do not
meet all the criteria for diagnosis of APS but are known to have aPL. In some cases,
these women were tested because of a prior false-positive test for syphilis with
subsequent identification of aPL. Women undergoing in vitro fertilization (IVF) have
been tested and found to have an increased incidence of aPL.99 However, a summary
of all published reports on studies of at least 100 patients indicates that positive aPL in
patients undergoing IVF does not influence pregnancy rates.99
In women who have a diagnosis of APS, meeting both clinical and laboratory
criteria, the chance for successful pregnancy is reduced. In these cases, treatment
seems to be a clear option, particularly in the case of patients with prior thromboembolic events. Current clinical guidelines support the use of subcutaneous heparin and
aspirin. This treatment should begin with a positive pregnancy test, continue
throughout pregnancy, and extend postpartum.
ACKNOWLEDGMENTS
The authors would like to thank John T. Kutteh for his assistance in the preparation
and submission of this article. His contributions are greatly appreciated, as he helped
to facilitate the timely submission of this article.
Antiphospholipid Antibody Syndrome
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I n h e r i t e d Th ro m b o p h i l i a s an d
A d v e r s e Preg n a n c y O u t c o m e s
A Review of Screening Patterns and
Recommendations
William B. Davenport,
MD
a
, William H. Kutteh,
MD, PhD, HCLD
b,
*
KEYWORDS
Pregnancy Inherited thrombophilias Recurrent pregnancy loss Preeclampsia
Intrauterine growth restriction Placental abruption OB/GYN
KEY POINTS
Historically, much controversy has existed regarding the association of inherited thrombophilias with adverse pregnancy outcomes.
The current guidelines do not recommend screening unless a personal or strong family
history of venous thromboembolism is present, but the authors’ survey of physician
screening patterns has suggested that up to 40% of physicians may screen contrary to
the current guidelines.
Over 90% of both general Obstetrician/Gynecologists and Reproductive Endocrinologists
are appropriately testing patients with recurrent pregnancy loss for anticardiolipin antibodies and the lupus anticoagulant with the overwhelming majority using indicated treatment during pregnancy.
This article summarizes the existing evidence for each inherited thrombophilia and
reviews the current guidelines.
INTRODUCTION
Three decades ago, antiphospholipid antibodies (aPL) were proposed to have a
causal association with recurrent pregnancy loss (RPL), suspected because of
placental clots that were observed after pregnancy loss with subsequent positive
serum aPLs. Following the hypothesis-inducing investigations, an association was
found between aPL and RPL. However, it was not until 1996 that Kutteh and
The authors have nothing to disclose.
a
Department of Obstetrics and Gynecology, University of Vermont, 89 Beaumont Avenue,
Given C262, Burlington, VT 05406, USA; b Department of Obstetrics and Gynecology, Vanderbilt University Medical Center, Fertility Associates of Memphis, 80 Humphreys Center, Suite
307, Memphis, TN 38120, USA
* Corresponding author.
E-mail address: wkutteh@fertilitymemphis.com
Obstet Gynecol Clin N Am 41 (2014) 133–144
http://dx.doi.org/10.1016/j.ogc.2013.10.005
obgyn.theclinics.com
0889-8545/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
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Davenport & Kutteh
colleagues1 found that treatment of pregnant women who have aPL syndrome with
heparin and aspirin increased the live birth rate to 80%.2
With a causal role of aPL established, research was driven by further hypotheses
that inherited thrombophilias may cause pregnancy losses via their resulting hypercoagulability and expanded to also include other adverse pregnancy outcomes,
including the effects on preeclampsia, intrauterine growth restriction (IUGR),
placental abruption, and stillbirth. The various case control trials that resulted have
yielded conflicting conclusions regarding inherited thrombophilias and adverse pregnancy outcomes, and randomized controlled trials are lacking. No causal role has
been established to date.3 The authors’ group performed a survey of the screening
and treatment patterns for thrombophilia in pregnancy among obstetricians (OBs)
and reproductive endocrinologists (REIs) regarding thrombophilias in pregnancy.
The authors found that many physicians may still screen and treat for inherited
thrombophilias beyond the recommendations. This article provides an overview of
the pathophysiology of the most common inherited thrombophilias and historical
findings of their relationships to adverse pregnancy outcomes. It also summarizes
the current recommendations for screening and treatment of inherited thrombophilias and presents recent practice patterns of physicians in response to this
evidence.
OVERVIEW
Inherited thrombophilia is defined as a genetic predisposition to venous thromboembolism (VTE), usually a genetic deletion or alteration of a functional protein in the coagulation cascade. The most common inherited thrombophilias include factor V Leiden
(FVL G1691A) mutation, prothrombin gene mutation (prothrombin G20210A), protein
C deficiency (PCD), protein S deficiency (PSD), methyltetrahydrofolate reductase
(MTHFR) mutation, and antithrombin III (AT) deficiency. Each of these has a common
role in inducing a hypercoagulable state via direct or indirect augmentation of prothrombin to thrombin, its active clot-inducing form (Fig. 1). Because hypercoagulability with inherited thrombophilias has been well established, screening of pregnant
women with a personal history of VTE has been generally well accepted in practice,
with the purpose of providing thromboembolic prophylaxis if needed. This practice
is supported by the most recent guidelines, and its acceptance is confirmed in the authors’ survey findings of physicians’ practices.4 Screening in the presence of a family
history of VTE has also been historically accepted but has recently been challenged as
not being founded on evidence.4–9 Subsequently, the practice is currently being reassessed, with some evidence against screening in women with a positive family history
of VTE.9
A larger controversy has existed in the recent past around the utility of screening for
inherited thrombophilias in women with a history of adverse pregnancy outcome or
loss. Several strong arguments exist against screening in this population. Perhaps
most importantly, only weak associations have been found between hypercoagulability and pregnancy outcomes; no causative relationship has been established.3 Even
more, many inherited thrombophilias are common in the general population, and
most of these women have normal pregnancy outcomes.10 From the standpoint of
thromboembolism prevention, some argue that inherited genetic aberrations in clotting proteins are less likely to be significant in the absence of a thromboembolic event
history and that screening this population is akin to screening the general population,
which has shown to be cost-ineffective.11 Because of these positions, recommendations are against screening women in this group.
Inherited Thrombophilias and Adverse Pregnancy
Fig. 1. Cascade of thrombus formation.
Despite the aforementioned arguments and published recommendations regarding
the utility of screening in pregnant women with a history of loss or adverse outcomes,
the authors’ findings have suggested that many physicians continue to screen this
population. These convictions are not unfounded, and several historical studies support this stance. Most studies in support of this practice hypothesize microthrombi,
thrombosis, and infarction of the placenta as contributing causes of pregnancy complications or loss.1,11,12 In addition, an argument exists that women with any type of
thromboembolic defect have a higher prevalence of pregnancy complications.13
Following is a summary of the available evidence regarding each inherited thrombophilia in relation to adverse pregnancy outcomes and the risk of VTE. All data reported
here are assuming an absence of personal or family history of VTE.
Factor V Leiden
Activated factor V is a clotting protein that works in conjunction with activated factor X
to directly convert prothrombin to thrombin. A specific mutant form of this protein, factor V Leiden (F5 c.1691G>A and p.Arg506Gln), is resistant to inactivation, leading to
higher amounts of activated factor V, more thrombin formation, and, thus, a hypercoagulable state (see Fig. 1). Although its heterozygous form is the most common
inherited thrombophilia, its prevalence is still low in the general population.4 Less
than 0.3% of these heterozygotes will have a VTE in pregnancy.4
Concerning adverse fetal outcomes, 2 recent comprehensive reviews of the literature have determined that carriers of FVL G1691A have an increased relative risk for
RPL (odds ratio [OR] 1.52, 95% confidence interval [CI] 1.06–2.19 and OR 2.02,
95% CI 1.60–2.55).14,15 However, the maternal-fetal medicine (MFM) network also
emphasized a low absolute risk (4.2%) of pregnancy loss in women with FVL
G1691A.15 No significant association exists between FVL G1691A and preeclampsia
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or small gestational age.15,16 Associations between placental abruption and FVL
G1691A are also lacking.17–19 However, a more recent MFM network case control
study, although confirming a lack of association with placental abruption, did find
an increase in fetal hypoxia-inducing factors in the placentas of mothers with FVL
G1691A compared with age-matched controls.20 The current guidelines agree that evidence is inadequate to recommend screening for factor V Leiden in women with
adverse pregnancy outcomes of any kind.4,9,11,14
Prothrombin
Prothrombin G20210A substitution mutation (F2 c.20210G>A) is the second most
common inherited thrombophilia, second only to heterozygous factor V Leiden. A
mutated form causes a deficiency in thrombin, with a resulting increase in the concentration of prothrombin in the plasma (see Fig. 1). VTE incidence with prothrombin
G20210A is low, with one early study suggesting prothrombin G20210A heterozygotes
to have an absolute risk of less than 0.5% and homozygotes to only reach 2% to 3%.
Concerning RPL, Bradley’s14 comprehensive literature review suggested that women
with this mutation were overall twice as likely to have RPL as those without the prothrombin G20210A mutation (OR 2.07, 95% CI 1.59–2.7), but the MFM network determined no association in their case control study and meta analysis.14,15,21 Both
literature reviews stated that no definitive conclusion could be made about RPL and
prothrombin G20210A because of a paucity of studies. There is consensus among
all published reviews of literature that no association exists between prothrombin
G20210A and preeclampsia or small for gestational age (SGA).15,16,22 One study
has suggested a correlation with placental abruption, but most have found no correlation between prothrombin G20210A and placental abruption.16,21,23 Accordingly, the
American Congress of Obstetricians and Gynecologists (ACOG) recommends against
screening for prothrombin G20210A in women with any history of adverse pregnancy
outcomes.4
Protein C Deficiency and Protein S Deficiency
Protein S and activated protein C, in combination, are necessary for the activation of
factors V and VIII, as summarized in Fig. 1. Therefore, a deficiency in either of these
proteins can result in a hypercoagulable state. Although the risk of VTE during pregnancy with either protein deficiency is up to 7% in the presence of a personal or family
history of VTE, the absolute risk of VTE in the absence of such history is 0.1% and
0.1% to 0.8%, respectively.4 Further, the prevalence of the disorders is only 0.2%
to 0.3% in the general population. No studies have found an association between protein C Deficiency (PCD) or Protein S Deficiency (PSD) and early pregnancy loss, IUGR,
or placental abruption. A review of literature from 2002 that included only 3 to 5 pertinent studies found an increased risk of preeclampsia with PCD (OR 21.5, CI 4.4–414.4)
and PSD (OR 12.7, CI 4.0–39.7), with an absolute risk of 1.4% and 12.3%, respectively. The same study suggested an increase in stillbirth among those with PSD
(OR 16.2, CI 5.0–52.3), with an absolute risk of 6%.23 However, because of the small
number of studies with relatively few participants, the ACOG currently does not
recommend screening for PSD or PCD in women with any history of adverse pregnancy outcomes.4
Antithrombin Deficiency
Antithrombin is a small protein that inactivates both factor Xa and thrombin, and
serves as a regulator of clot formation (see Fig. 1). A rare deficiency in this protein
results in severe coagulopathy, increasing the risk up to 25 times those with normal
Inherited Thrombophilias and Adverse Pregnancy
antithrombin levels. Women with antithrombin III deficiency do indeed have an
increased risk of embryonic demise and fetal death compared with the general
population.24–27 However, because of the low prevalence (1 out of 2500), screening
is not recommended in those with a prior pregnancy loss. Studies observing its
effects on other adverse pregnancy outcomes are lacking, also due to low
prevalence.
Methylene Tetrahydrofolate Reductase
Methylene tetrahydrofolate reductase (MTHFR) is one of 3 enzymes that is essential
for the metabolism of folic acid and is responsible for directly converting homocysteine to methionine. A mutation in this enzyme can cause increased levels of substrate
homocysteine. Hyperhomocysteinemia debatably can result in a hypercoagulable
state at the endothelium and has historically been associated with RPL28; but its relationship to thrombosis is only theoretical.29 Two predominant mutations exist, MTHFR
C677T and A1298C. Most recently, however, evidence has suggested that homocysteine is only a marker for thrombosis rather than a cause and that it must be combined
with other thrombophilias to present any significant risk of VTE.29–33 The existing data
suggest an absence of any correlation with preeclampsia, IUGR, or placental abruption. However, the ACOG and the MFM network have determined that data are insufficient to determine the correlation.20,22,34 Accordingly, the ACOG does not
recommend screening women for MTHFR with any history of adverse fetal outcomes
or with a history of VTE.4
MTHFR polymorphisms are also associated with an increased risk of neural tube
defects (NTDs) because of low serum folic acid.35 Women delivering a baby with an
NTD have more than twice the incidence of having an MTHFR C677T polymorphism.36
In addition, the combination of MTHFR C677T polymorphism with MTHFR A1298C
polymorphism may further increase the risk of NTDs.37 Therefore, the authors think
it is prudent to treat these patients with amounts of folic acid similar to those used
to treat patients who had a prior infant with an NTD.36–38
Combined Defects
Most studies have only observed VTE risks on pregnancy outcomes with individual
thrombophilias. However, a few have assessed combinations of these disorders,
such as FVL G1691A/prothrombin G20210A double heterozygosity and FVL
G1691A in the presence of an MTHFR mutation, concluding that an additive or synergistic effect is present.26,39–44 This distinction should be made, although further exploration of this topic is beyond the scope of this review.
Acquired Thrombophilias
Because of their nongenetic preponderance, acquired thrombophilias are classified
separately from inherited thrombophilias and are summarized only briefly for the purpose of contrast because these disorders are also beyond the scope of this review.
The most common acquired thrombophilia involves the presence of aPL. The presence of these antibodies has been associated with second-trimester as well as firsttrimester pregnancy loss.45,46 Therefore, it is recommended to screen for the most
common of these antibodies (lupus anticoagulant, anticardiolipin, and anti-beta2
glycoprotein) in women with a history of more than 2 or 3 first-trimester losses and
in women with one or more loss after 20 weeks with no alternative explanation.4,11
It is also well established that treating these thrombophilias with heparin and aspirin
improves pregnancy outcomes.1,2
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Davenport & Kutteh
TREATMENT OF INHERITED THROMBOPHILIAS
Given the current lack of evidence to support an association between adverse pregnancy outcomes and inherited thrombophilias, it is currently not recommended to
treat inherited thrombophilias with adverse pregnancy outcomes alone in mind.4 However, treatment is justifiable in some patients with known thrombophilias who are at an
increased risk of VTE during pregnancy.47 The ACOG’s treatment recommendations
have been abbreviated and summarized in Table 1. They specifically address thresholds at which to begin anticoagulants, which can be used to treat all known inherited
thrombophilias except MTHFR mutations. The guidelines do not address the treatment of known MTHFR mutations for VTE prevention, but the traditional treatment
has been vitamin B and folate. However, evidence now suggests that vitamin B supplementation does not reduce VTE incidence.32,48 Therefore, if one decides to treat
these mutations, folate alone may be the best choice.
Table 1
Recommended thromboprophylaxis for pregnancies complicated by inherited thrombophilias
a
Clinical Scenario
Antepartum Management
Postpartum Management
Low-risk thrombophiliaa
without previous VTE
Surveillance only or
prophylactic heparin
Surveillance only if no risk
factors; postpartum
anticoagulation if risks
factorsb
Low-risk thrombophiliaa
with a single previous
episode of VTE; not
receiving long-term
anticoagulation therapy
Surveillance only or
prophylactic heparin
Postpartum anticoagulation
therapeutic or intermediatedose heparin
High-risk thrombophiliac
without previous VTE
Prophylactic heparin
Postpartum anticoagulation
therapy
High-risk thrombophiliac
with a single previous
episode of VTE; not
receiving long-term
anticoagulation therapy
Prophylactic, intermediatedose or adjusted-dose
heparin
Postpartum anticoagulation
therapy or intermediate- or
adjusted-dose heparin
Thrombophilia or no
thrombophilia with 2 or
more episodes of VTE;
not receiving long-term
anticoagulation therapy
Prophylactic or therapeuticdose heparin
Postpartum anticoagulation
therapy or therapeutic-dose
heparin for 6 wk
Thrombophilia or no
thrombophilia with 2 or
more episodes of VTE;
receiving long-term
anticoagulation therapy
Therapeutic-dose heparin
Resumption of long-term
anticoagulation therapy
Low-risk thrombophilia: factor V Leiden heterozygous; prothrombin G20210A heterozygous;
PCD or PSD.
b
First-degree relative with a history of a thrombotic episode before 50 years of age or other major
thrombotic risk factors (eg, obesity, prolonged immobility).
c
High-risk thrombophilia: antithrombin deficiency; double heterozygous for prothrombin
G20210A mutation and factor V Leiden; factor V Leiden homozygous or prothrombin G20210A
mutation homozygous.
Adapted from James A. Practice bulletin no. 123: thromboembolism in pregnancy. Obstet Gynecol 2011;118(3):718–29; with permission.
Inherited Thrombophilias and Adverse Pregnancy
PHYSICIAN PRACTICE PATTERNS
The authors’ group distributed questionnaires regarding screening patterns of physicians for thrombophilia in pregnant women. Surveys were given to physicians only and
were distributed at the beginning of 4 national meetings to OBs and REIs. The survey
explored the clinical scenarios in which each physician would screen for thrombophilias, which tests they routinely ordered once the decision to order an evaluation
had been made, and the treatment modalities used after an abnormal test result. Participants were given the survey before the meeting and were asked to respond to the
survey based on their current practice pattern. Response rates at individual meetings
ranged from 76% to 87% and were not considered significantly different between
meetings. A total of 186 surveys were evaluated.
Thrombophilia Testing Criteria
Almost all physicians (97%) reported that a personal history of thrombosis warranted
screening, and slightly fewer reported screening in patients with a family history of
thrombosis (82%) (Table 2). Most physicians (90%) reported testing a patient with
an unexplained fetal death at more than 20 weeks’ gestation, but still 46% said they
would screen a patient with a single loss at less than 20 weeks’ gestation. Most physicians (94%) considered women with a history of 3 or more recurrent first-trimester
miscarriages to be candidates for a thrombophilia evaluation, and 76% indicated
that they offered testing after 2 early losses. Several physicians reported screening patients based on the fetal outcome of a prior abruption, with 62% screening patients if
the abruption resulted in fetal demise compared with 37% if it resulted in a live birth;
42% screened a patient with a prior IUGR baby. Only a minority of REIs reported
screening for assisted reproductive technology, whether it was a new patient (2%)
Table 2
Candidates for thrombophilia evaluation
ALL MDsa (%)
OB/GYN (%)
REI (%)
P
3 RPL
173/185 (94)
72/77 (94)
101/108 (94)
.57
2 RPL
141/185 (76)
55/77 (71)
86/108 (80)
.13
ART failed attempt
29/104 (28)
N/A
29/104 (28)
—
ART new attempt
2/102 (2)
N/A
2/102 (2)
—
Personal history thrombosis
181/186 (97)
75/78 (96)
106/108 (98)
.44
Family history thrombosis
150/183 (82)
61/77 (79)
89/106 (84)
.59
Stillbirth or IUFD >20 wk
164/183 (90)
66/78 (85)
98/105 (93)
.35
Spontaneous pregnancy lossb
81/176 (46)
31/76 (41)
50/100 (50)
.72
Prior IUGR
76/181 (42)
33/77 (43)
43/104 (41)
.64
Abruption, demise
112/181 (62)
50/75 (67)
62/106 (58)
.69
Abruption, live birth
65/177 (37)
27/73 (37)
38/104 (37)
.59
Personal history thrombophilia
161/183 (88)
63/77 (82)
98/106 (92)
.06
Prior baby with NTD
32/182 (18)
7/76 (9)
25/106 (24)
.01c
Sister with baby with NTD
23/181 (13)
5/76 (7)
18/105 (17)
.03c
Abbreviations: ART, assisted reproductive technology; GYN, gynecologist; IUFD, intrauterine fetal
demise; N/A, not applicable.
a
Not all participants answered all survey questions, so the numbers are not equal to the total
number of respondents.
b
Spontaneous pregnancy loss defined as less than 20 weeks.
c
Significantly different results between OB/GYNs and REIs.
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Davenport & Kutteh
or a previously failed cycle (28%) (see Table 2). There were no significant differences
among specialties in testing criteria except that significantly more REIs offered
screening for a personal or family history of NTDs than did OBs.
Thrombophilia Tests Used
When assessing which thrombophilia tests were routinely ordered in each physician’s
thrombophilia evaluation, almost all participants reported ordering anticardiolipin antibodies (98%) and lupus anticoagulant (97%) (Table 3). Most physicians included
DNA testing for prothrombin G20210A (76%) and FVL G1691A mutations (90%)
with no difference between specialties. Significantly more REIs reported screening
for PCD (75% vs 53%; P<.01), PSD (73% vs 55%; P<.01), and AT deficiency (60%
vs 42%; P 5 .01) (data not shown). More than a third of all physicians reported testing
for polymorphisms on MTHFR (see Table 3).
Thrombophilia Treatment Patterns
The final section of the authors’ survey examined which thrombophilias each physician
treated and the treatment modality of each. Most REIs and generalists (80%–90%) reported treating patients who had an acquired thrombophilia, homozygous factor V Leiden, PCD, or PSD and treated homozygous and heterozygous disorders with equal
frequency between specialties. However, more REIs treated an abnormal random homocysteine level in pregnancy than did OB/GYNs (80% vs 45%, P<.01) (data not
shown). Concerning treatment modalities, most treated aPL, prothrombin G20210A,
PCD, PSD, and AT with heparin, either alone or in combination with aspirin (Table 4).
DISCUSSION
The authors assessed how actual reported treatment patterns compared with the current guidelines by the ACOG. As expected, most of the practice patterns need no
modification in order to remain in compliance with the most recent recommendations.4,11 However, several practice patterns varied from the most recent guidelines.
As detailed earlier, the ACOG’s most recent recommendations hold that evidence is
insufficient to screen for thrombophilias based on previous adverse pregnancy outcomes (IUGR, stillbirth, abruption, or pregnancy loss) alone in the absence of additional risk factors for thrombosis.4 However, around 40% of physicians treated
these women, suggesting that many are still following older literature, which suggests
that inherited thrombophilias are associated with adverse pregnancy outcomes.
Table 3
Thrombophilia testing routinely being ordered by physicians
Anticardiolipin antibody
a
ALL MDsa (%)
OB/GYN (%)
REI (%)
P
181/185 (98)
75/78 (96)
106/107 (99)
.72
Lupus anticoagulant antibody
180/186 (97)
74/78 (95)
106/108 (98)
.25
Antiphospholipid panel
147/183 (80)
67/78 (86)
80/105 (76)
.02b
Factor V Leiden G1691A
166/185 (90)
71/78 (91)
95/107 (89)
.41
Activated protein C resistance
98/182 (54)
33/77 (43)
65/105 (62)
.04b
Prothrombin G20210A
140/184 (76)
53/77 (69)
87/107 (81)
.07
MTHFR
75/178 (42)
20/73 (27)
56/105 (53)
<.01b
Not all participants answered all survey questions, so the numbers are not equal to the total number of respondents.
b
Significantly different results between OB/GYNs and REIs.
Inherited Thrombophilias and Adverse Pregnancy
Table 4
Treatment patterns for thrombophilias (all physicians)a
Heparinc
and/or
Aspirin
nb
Aspirin
Only
Vitamin B
and/or Folic
Acid
Anticardiolipin antibody
135
109
81%
19
14%
8
6%
Lupus anticoagulant antibody
128
107
84%
16
13%
7
5%
Antiphospholipid panel
107
86
81%
14
13%
8
7%
Factor V Leiden
121
108
89%
3
2%
8
7%
Activated protein C resistance
52
41
79%
5
10%
7
13%
Prothrombin mutation
78
70
90%
5
6%
4
5%
MTHFR C677T
61
12
20%
1
2%
59
97%
PCD
71
59
83%
8
11%
6
8%
PSD
67
54
81%
7
10%
7
10%
Antithrombin deficiency
47
41
87%
1
2%
4
9%
Anti-B2 glycoprotein
18
13
72%
2
11%
3
18%
Hyperhomocysteinemia
51
5
10%
1
2%
37
73%
a
The numerator is equal to the number of physicians who treated the patient with the indicated
treatment modality, and the denominator is equal to the number of physicians who both treated
the indicated thrombophilia and answered the question concerning treatment modality. Not all
participants answered all survey questions, so the numbers are not equal to the total number of
respondents.
b
Not all participants answered all survey questions, so the numbers are not equal to total number
of respondents.
c
Heparin includes both low-molecular-weight heparin and unfractionated heparin in either prophylactic or therapeutic doses.
Nevertheless, the authors agree that evidence is not adequate to make a definitive association between these pregnancy outcomes and inherited thrombophilias.
For those who meet the appropriate criteria for inherited thrombophilia screening,
the ACOG recommends that the following tests be ordered: factor V Leiden, prothrombin G20210A, protein C and S, and antithrombin III.4 Most physicians currently order
all of the aforementioned tests; but greater than 40% of physicians reported also
ordering MTHFR and homocysteine levels in their thrombophilia screen, both of which
are not considered part of the recommended thrombophilia evaluation according to
the ACOG. However, some of these decisions may have been based on the wellsupported association of MTHFR polymorphisms with NTDs.36–38
Concerning treatment, the ACOG recommends that only acquired thrombophilias
be treated for RPL and then with heparin and aspirin. Although more than half of the
physicians appropriately treat these antibodies, a large percentage still only use heparin or aspirin, which has been shown to be inferior to combination therapy.1,2 Most of
the physicians who treat inherited thrombophilias appropriately use heparin with or
without aspirin (see Table 4).
SUMMARY OF CURRENT STATE OF RESEARCH AND FUTURE DIRECTION
Overall, discrepancies in the literature do still exist concerning appropriate screening
and management of those with prior adverse pregnancy outcomes. Large prospective, multicentered trials and evaluation of national databases, which are currently being conducted, will be required to clearly determine the risks associated with inherited
141
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Davenport & Kutteh
thrombophilias in this regard. Until these data are available, physicians should
compare their current practice patterns for thrombophilia screening with the guidelines in the ACOG practice bulletin, with an emphasis on individualizing their management when the data are not sufficient.
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48. Lonn E, Yusuf S, Arnold MJ, et al. Homocysteine lowering with folic acid and B
vitamins in vascular disease. N Engl J Med 2006;354(15):1567–77.
R e c u r re n t M i s c a r r i a g e C l i n i c s
M.M.J. Van den Berg, MD, Rosa Vissenberg,
Mariëtte Goddijn, MD, PhD*
MD,
KEYWORDS
Recurrent miscarriage Recurrent miscarriage clinic Quality of care
Guideline adherence Patient preferences
KEY POINTS
A recurrent miscarriage (RM) clinic offers specialist investigation and treatment of women
with recurrent first- and second-trimester miscarriage.
RM care preferably should be provided by only one doctor per couple.
A treatment strategy should be designed with the couple for a subsequent pregnancy.
Evidence-based guidelines are necessary for the facilitation of evidence-based practice
and to reduce practice variation between professionals.
Guideline adherence can be achieved by implementation efforts.
INTRODUCTION
A miscarriage is the spontaneous loss of a clinically established intrauterine pregnancy
before the fetus has reached viability. It includes pregnancy losses until the maximum
of 24 weeks of gestation.1 Between 10% and 15% of all clinically recognized pregnancies result in a spontaneous miscarriage. However, the overall prevalence of pregnancy losses, including biochemical pregnancies, is generally assumed 4 to 5 times
higher.1 Approximately one-quarter of all women experience at least one miscarriage
during their lives.2,3 In conclusion, a miscarriage is a frequent event and it is known that
a miscarriage has a huge impact on a patient’s life.
Up to 5% of all couples face recurrent miscarriage (RM). The definition may vary but
starts when at least two or more miscarriages have occurred.4,5 The sequence of the
miscarriages is not necessarily consecutive.4,6
A RM clinic offers specialist investigation and treatment of women with recurrent
first- and second-trimester miscarriages. It is an outpatient clinic with reproductive
The authors have nothing to disclose.
Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Academic
Medical Center, H4-205, PO Box 22660, Amsterdam 1100 DD, The Netherlands
* Corresponding author.
E-mail address: m.goddijn@amc.nl
Obstet Gynecol Clin N Am 41 (2014) 145–155
http://dx.doi.org/10.1016/j.ogc.2013.10.010
obgyn.theclinics.com
0889-8545/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
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Van den Berg et al
gynecologists specialized in evidence-based RM care. This consultant-led clinic provides a dedicated and focused service to couples who have experienced at least two
prior miscarriages.
GUIDELINES
Guideline Adherence
To improve the quality of care for RM, guidelines have been developed. These guidelines address the facilitation of evidence-based practice and reduce practice variation
between professionals.7 Couples with RM are often not treated according to the most
up-to-date clinical evidence, as summarized in recent guidelines.8,9 Ineffective management of couples with RM is caused by underdiagnostics as well as overdiagnostics, resulting in unnecessary tests and costs.10 This barrier and other barriers to RM
management are shown in Box 1. The introduction of new guidelines alone is not
enough to prevent this ineffective management. Guideline implementation research
shows that to achieve a high level of guideline adherence, implementation efforts
are necessary.11,12 So far, it is not obvious which implementation strategy to apply
to improve guideline adherence and, meanwhile, quality of care in couples with RM.
Guideline adherence could be improved with a multifaceted implementation strategy. In total, 23 quality indicators for care in couples with RM have been identified.13
These can be used to measure and monitor care for RM patients. These guidelines
improved remarkably after introduction of the developed implementation strategy.13
Another essential step in the implementation process of guidelines is qualitative
research to identify barriers to and facilitators for guideline adherence.7,11 One study
identified barriers in management of RM in four domains: the guidelines, professionals, patients, and organization by semistructured interview among professionals
and patients.14 The most important identified barriers for guideline adherence were
the guidelines being too complicated, lack of up-to-date patient information,
and lack of detailed knowledge about family history.14 Based on the detected
Box 1
Barriers to high-quality RM management
Guidelines
The definition of RM differs: two versus three miscarriages and consecutive versus nonconsecutive miscarriage.
Few good RCTs have been performed to investigate diagnostic and treatment options.
Organization
Not every hospital has a recurrent miscarriage clinic/early pregnancy unit.
Not every hospital works with a RM expert.
Not every hospital offers participation in RCTs.
Professionals
Doctors want to offer treatment despite a lack of evidence.
Patients
Patients have a strong will to perform diagnostic tests despite a lack of evidence.
Patients have a strong will to start treatment despite a lack of evidence.
Recurrent Miscarriage Clinics
determinants for nonadherence and the barriers experienced by professionals and
patients, an implementation strategy for improvement could be developed.
Guidelines state that all couples who suffer from RM should be offered advice and
referred to a specialist clinic with appropriately trained health care professionals.15
Couples with unexplained RM should be informed about their individual chances of
success in a next pregnancy.16 Tender loving care (TLC) and health advice are the
two established treatments of RM (discussed later).7 Health advice includes intake
of folic acid, restriction of the intake of coffee, stopping smoking and drinking alcohol,
and lifestyle advice and/or dietary measures in cases of overweight.7 For women with
RM and a subsequent confirmed pregnancy test, arrangements should be in place for
an ultrasound scan and for receiving shared antenatal care in a high-risk obstetric
clinic.15 It is extremely important that all staff dealing with RM couples are trained in
emotional aspects of pregnancy loss. In this way, immediate support can be provided
and patients have direct access to specialist counseling.15 The aim is to make all
health professionals providing early pregnancy care aware of the current approach
to this problem.17
LOGISTICAL REQUIREMENTS
Couples who have suffered two or more miscarriages should be referred to a RM
clinic. Fig. 1 provides a flowchart for the entry in a RM clinic. Preferably a patient information brochure has been sent to couples before their first visit to the clinic. This
way, a couple’s expectations can be met. Box 2 and Fig. 2 give an overview of the
tools provided by RM clinics.
Location
The service is often situated in a gynecology outpatient clinic or near an early pregnancy unit. Avoid, whenever possible, locating a clinic near an antenatal clinic to
reduce any distress experienced by women seeing ongoing pregnancies while waiting.
Rooms
A room is necessary for taking history and examination. It is important that the room
can be locked to guarantee privacy while women are changing and being examined. In
certain units, a separate room is used to perform the transvaginal sonography. These
rooms should be warm and have good lighting for vaginal examinations. Another
separate room for breaking bad news may be valuable. In this way, women are
allowed to have some time to reflect and compose themselves before proceeding
with further management. It is preferable that this room has telephone access to allow
calls to relatives or friends.
Staffing
All RM clinics should have a consultant with a special interest in RM. RM care should
be provided by only one doctor per couple. Multidisciplinary support should be provided by other departments, such as clinical genetics, an early pregnancy assessment
unit, pathology, radiology, internal medicine, endocrinology, and/or hematology departments. It is important that all staff dealing with RM couples are trained in emotional
aspects of pregnancy loss. In this way, immediate support can be provided and every
couple has direct access to specialist counseling.15 The aim is to make all health
professionals providing early pregnancy care aware of the current approach to
manage RM.17
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Referral by another
specialist
Selfreferral by patient
First appointment is
scheduled
A patient information
brochure and patient
questionnaire is sent to the
home adress of the
couple
First appointment
- Medical, obstetric, lifestyle, family history
and history with regard to the prior
miscarriages is obtained
- Diagnostic tests are performed when
indicated
- Counseling about causes / cures for RM
Second appointment
(same doctor)
- Results of the diagnostic tests
performed are discussed
- Couples are treated if indicated
- Treatment plan is discussed for a future
pregnancy
- Recruitment for randomized controlled
trial or cohort study
Pregnant
Not pregnant
Follow-up of pregnancy and
emotional support according
to the support plan performed
by the same doctor
- Emotional support when
needed by the same doctor or
counsellor
- When indicated: referral to the
fertility unit
Fig. 1. Flowchart for entry into an RM clinic.
Equipment
For follow-up of a future pregnancy to confirm a miscarriage, the ability to perform
transvaginal and/or transabdominal scan is necessary. It is preferable that the ultrasound has the ability to store copies of all images to be given to the women if
Recurrent Miscarriage Clinics
Box 2
Tools for recurrent miscarriage clinics
A RM specific protocol for diagnosis & treatment should be available so that all couples
receive the same standard care that is in line with the information on the patient
information brochure.
Proper work-up for diagnosis and treatment is indicated.
Unproven therapies should be used only in the setting of a properly conducted randomized
trial.
Couples with unexplained RM should be informed about their individual chances of success
in a next pregnancy.
A plan should be made how to offer good support during the first trimester in the next
pregnancy.
Because the chance of a successful pregnancy is still promising, treatment should focus on
supportive care, where possible.
Involve the male partner.
Couple-based psychological care should be offered to couples with RM.
An RM clinic should preferably be organized in a way that couples receive individual care
from one doctor per couple.
A patient information brochure must be available and preferably sent to couples before their
first visit, so they know what to expect from the RM clinic.
requested. Also an electronic database is advisable for documentation of all images.
This gives an opportunity to exchange images with an early pregnancy unit.
Record Keeping
History, examination, and scan findings need to be documented and archived in the
women’s patient notes or in a database that is secured with a password-based access. A standardized protocol should be used for the documentation of history and
examination. This way, all patients are asked the same questions and the chance of
forgetting something is low.
Laboratory Services
A basic requirement is access to hematology and biochemistry to facilitate RM diagnostic work-up.
One-Stop Recurrent Miscarriage Clinics
Some clinics are organized as an one-stop RM clinic.18 When a couple is referred to a
RM clinic, they receive a letter with a set of investigation forms and are advised to
take blood tests. This way, the results of the blood tests are known and can be discussed when the couple attends the clinic for the first time. During the same consultation, history and physical examination are documented, which leads to a
management plan. Couples only attend the RM clinic once and do not need any unnecessary repeat consultations. Before leaving the clinic, each couple is seen by a
nurse counselor. They are given a direct telephone number to the antenatal assessment area (AAA), where all pregnancies are followed-up by the counselor. When a
couple is pregnant, they call the AAA to receive follow-up scans and antenatal
care. This one-stop clinic reduced the interval of visits by 36% (206.6–130.4 days;
P<.001) and reduced the number of visits by 60% (2.5–1; P<.002).18 This approach
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Van den Berg et al
1. Location
Do:
- RM clinic situated In the gynecology outpatient
clinic or near the Early Pregnancy Unit.
Don’t:
- RM clinic situated near the antenatal clinic
2. Rooms
Do:
- A room for taking history and examination.
- A separate room to break away bad news
Optional:
- A separate room to perform the TVS
3. Staffing
Do:
- Counselor with a special interest in recurrent
miscarriage
- Multidisciplinary support should be provided by
other departments; genetics, an EPAU, pathology,
radiology, internal medicine, endocrinology and/or
hematology departments
4. Equipment
Do:
- Transvaginal and/or transabdominal scan with
the option to store hard copies and/or electronical
database
5. Record keeping
Do:
- Patient’s file or a database with a
password based access
- A standardized protocol should be used for the
documentation of the history and examination.
6. Laboratory services
Do:
- Access to hematology, endocrinology and
biochemistry lab services
Fig. 2. Flowchart of logistical requirements for a RM clinic.
provides no patient-centered care, however. There is no explanation as to which
diagnostic test is performed. Also, not all couples need to go through all diagnostic
tests. Preferably, diagnostic work-up is based on proper history taking and individually tailored. Most diagnostic tests should only be performed on indication.
Recurrent Miscarriage Clinics
DOCTOR PREFERENCES
Diagnostic Tests
When a couple is seen at first consultation for RM, a detailed history is taken with regard to prior miscarriages and medical, obstetric, lifestyle, and family history. The decision to perform diagnostic investigations depends on the medical history.
Diagnostic tests should only be carried out if the test can either give insight in the
prognosis of an individual patient or if the established cause can be treated effectively. Diagnostic tests are performed and treatments are described despite a lack
of evidence. Before introducing new diagnostic investigations in clinical practice,
these tests should be evaluated thoroughly. The increasing costs of health care
have been calling for elimination of ineffective medical testing.10 Women with RM
are often desperate and can be demanding. In clinical practice, it has been shown
that too many diagnostic investigations and unproved treatments are performed in
women with RM. This is a result of doctors who find it difficult to resist insistent
women.8
Many of the diagnostic tests available for couples with RM give no information
with regard to the prognosis in a future pregnancy. There is also a lack of evidence
of potential treatment options in cases of a positive test result. Therefore, there is a
need for evidenced-based guidelines, based on prospective cohort studies for prognostic purposes and randomized controlled trials (RCTs) to investigate the usefulness of the treatment options available for RM couples.
Work-Up
The guidelines of the Association of Early Pregnancy Units suggest that patients
should not be subjected to tests without a proper plan of further follow-up and management (www.earlypregnancy.org.uk). It is important that both partners are aware of
what is going to happen. The couple should be prepared for the fact that in a majority
of cases no cause is found for the RM. Encourage the partner’s participation and
encourage the couple to talk about their fears and anxieties. Diagnostic testing should
not be done only to reassure patients that something is being done. If diagnostic tests
are performed, make sure that an explanation is given of all tests before taking blood
samples. Reassure the couple that all known risk factors for RM will be explored.
Discuss lifestyle end preconceptual care with the couple as available treatment plans.
This prepares the couple for their future consultation. If a couple achieves a pregnancy, a doctor should arrange ultrasound scanning at 6 weeks’ gestation and thereafter every week or 2 weeks, after discussing with the couple, for maternal assurance
until seen in the antenatal booking clinic (www.earlypregnancy.org.uk). It is important
to discuss a treatment plan for a future pregnancy with the couple. Not all couples
want to have an ultrasound scan every other week. It is important that the doctor listens to the patient.19,20 Management of women with RM based on emotional support
supplemurrent approach to this proented by ultrasound scan in early pregnancy has
success rates of between 70% and 80%. Individual changes depend on the number
of prior miscarriages and, more importantly, female age.21,22
Scientific Research Programs
For more than 50% of women with RM, no underlying cause is found. This is frustrating
for couples but also for clinicians and, therefore, it is tempting to start empiric treatment. Treatments of the RM population are often introduced without evaluating
effectiveness. The only way to improve quality of care, however, is to apply an
evidence-based approach.
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Scientific research is necessary to study the effectiveness of new interventions, to
study patient preferences, and to evaluate health care and costs or other outcomes.
Cooperation between multiple centers, nationally and internationally, will facilitate
research projects. Research networks will improve the infrastructure for scientific
studies. This leads to a faster recruitment of patients in trials and better and faster
implementation of study results but also standardization of care.
Patient data of women visiting the RM clinics should be recorded in databases to
obtain large cohorts of RM patients. These anonymous data can be used for both scientific research projects and evaluation of health care.
PATIENT PREFERENCES
Psychological and Relational Consequences of Recurrent Miscarriage
Experiencing RM can be a traumatic event and is often accompanied by negative
emotional distress.23 Different psychological and psychiatric effects can be induced.
Feelings of grief, lowered self-esteem, guilt, anger, and depression and anxiety disorders are common after miscarriage but also during the subsequent pregnancy.24,25
Anxiety is the predominant response to RM.25–27 Different prevalence rates have
been described for depressive symptoms, varying from 10% to 30%.27–30 Symptoms
of anxiety and depression can be present for 6 months after a pregnancy loss.25,28,31
Psychological reactions and grief reactions after RM are different in women than in
men. Women are more distressed than men after RM and men have lower anxiety
levels.24,32,33 Unlike women, men do not react with an increased depressive reaction.
Men grieve but less intensely and enduringly than their partners.24 Some men feel
burdened by their wives’ grief or depressive reactions.31 These gender differences
may worsen or have a negative impact on the psychological adjustment and marital
relationships in RM couples. Conflicting reactions may affect couples’ interactions
and promote depressive reactions in the women. Low marital adjustment and sexual
changes after RM have been reported.24,27 Data on whether a couple’s relationship is
adversely affected by RM are conflicting. One study does not describe a negative
impact on the relationship.24 But there is also evidence that women with a history of
RM were at a higher risk of their relationships ending compared with women without
a history of miscarriage.34
Supportive Care
A majority of women with RM are classified as having unexplained RM. For these patients, no effective treatment intervention exists. Current guidelines advise supportive
care for women with (unexplained) RM during the next pregnancy.7 The guidelines of
the Association of Early Pregnancy Units suggest that all staff members should be
trained in emotional aspects of early pregnancy loss and offer bereavement counseling (www.earlypregnancy.org.uk). Offering so-called TLC, which consists of reassurance and psychological support, has led to an improvement in pregnancy
outcome after unexplained RM in controlled studies.16,21,22,35 Live birth rates up to
85% have been reported after supportive care. These studies were of low quality,
however, because a clear definition of TLC is lacking and the study populations
were too small. The supportive care offered in earlier studies varied widely and no
clear definition of supportive care exists. How supportive care is defined and experienced depends on the perception of clinicians and patients and, therefore, is difficult
to analyze as a clear outcome measure.
Because pregnancy-related fear may have a negative impact on the course of pregnancy and delivery, interventions to reduce anxiety are highly recommended.36 It is not
Recurrent Miscarriage Clinics
clear from the literature whether anxiety might be reduced due to supportive care or
treatment in an RM clinic. One study showed that offering supportive care in a RM
clinic does not significantly change anxiety levels.26 This was only investigated in
one study and the study population was too small to draw final conclusions about
reduction of anxiety levels by supportive care.
There is limited evidence on the effect of RM clinics on psychological outcomes.
Possible explanations for this are that supportive care should be more accurately
defined and that analyzing supportive care as an outcome remains difficult.
Patient Preferences and Perspectives
Women’s perceptions and preferences for supportive care options have been studied in qualitative and quantitative research.19,20 Women with RM prefer the following
supportive care option for their next pregnancy: a plan with one doctor, who shows
understanding, takes them seriously, has knowledge of their obstetric history, listens
to them, gives information about RM, shows empathy, informs on progress, and enquires about emotional needs. Also, there is a need for ultrasound examination during symptoms, directly after a positive pregnancy test, and every 2 weeks. If a
miscarriage occurs, most women prefer to talk to a medical or psychological professional afterward. A majority of women have a low preference for admission to a
hospital.20
Couples do not always experience the supportive care of health professionals as
optimal.31 An important task for clinicians is to discuss with couples what their preferences are for supportive care and to make a plan for the next pregnancy. This improves patient-centered care.
RECOMMENDATIONS
RM patients are vulnerable and should receive good clinical supportive care. A RM
clinic is necessary to provide this care. Couples can be guided by one doctor and a
plan can be made together with the couples for a future pregnancy. Also, by working
with a specific protocol, all patients receive the same standard care.
All women who present with RM should have access to a specialized RM clinic with
appropriately trained health care professionals.15
REFERENCES
1. Rai R, Regan L. Recurrent miscarriage. Lancet 2006;368(9535):601–11.
2. Stephenson M, Kutteh W. Evaluation and management of recurrent early pregnancy loss. Clin Obstet Gynecol 2007;50(1):132–45.
3. Stern JJ, Dorfmann AD, Gutierrez-Najar AJ, et al. Frequency of abnomral karyotypes among abortuses from women with and withouw a history of recurrent
spontaneous abortion. Fertil Steril 1996;65(2):250–3.
4. Jaslow CR, Carney JL, Kutteh WH. Diagnostic factors identified in 1020 women
with two versus three or more recurrent pregnancy losses. Fertil Steril 2010;
93(4):1234–43.
5. Raijcan-Separovic E, Qiao Y, Tyson C, et al. Genomic changes detected by array
CGH in human embryos with developmental defects. Mol Hum Reprod 2010;
16(2):125–34.
6. van den Boogaard E, Kaandorp SP, Franssen MT, et al. Consecutive or nonconsecutive recurrent miscarriage: is there any difference in carrier status? Humanit Rep 2010;25(6):1411–4.
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7. Jauniaux E, Farquharson RG, Christiansen OB, et al. Evidence-based guidelines
for the investigation and medical treatment of recurrent miscarriage. Hum Reprod
2006;21(9):2216–22.
8. Franssen MT, Korevaar JC, van der Veen F, et al. Management of recurrent
miscarriage: evaluating the impact of a guideline. Hum Reprod 2007;22(5):
1298–303.
9. van den Boogaard E, Hermens RP, Verhoeve HR, et al. Selective karyotyping in
recurrent miscarriage: are recommended guidelines adopted in daily clinical
practice? Hum Reprod 2011;26(8):1965–70.
10. Berwick DM, Hackbarth AD. Eliminating waste in US health care. JAMA 2012;
307(14):1513–6.
11. Bero LA, Grilli R, Grimshaw JM, et al. Closing the gap between research and
practice: an overview of systematic reviews of interventions to promote the implementation of research findings. The Cochrane Effective Practice and Organization of Care Review Group. BMJ 1998;317(7156):465–8.
12. Grol R. Personal paper. Beliefs and evidence in changing clinical practice. BMJ
1997;315(7105):418–21.
13. van den Boogaard E, Goddijn M, Leschot NJ, et al. Development of guidelinebased quality indicators for recurrent miscarriage. Reprod Biomed Online
2010;20(2):267–73.
14. van den Boogaard E, Hermens RP, Leschot NJ, et al. Identification of barriers for
good adherence to a guideline on recurrent miscarriage. Acta Obstet Gynecol
Scand 2011;90(2):186–91.
15. Royal college of obstetricians and gynaecologists. Standards for gynaeacology:
chapter 4 recurrent miscarriage. 2008. Available at: http://www.rcog.org.uk/
womens-health/clinical-guidance/investigation-and-treatment-couples-recurrentmiscarriage-green-top-.
16. Brigham SA, Conlon C, Farquharson RG. A longitudinal study of pregnancy outcome
following idiopathic recurrent miscarriage. Hum Reprod 1999;14(11):2868–71.
17. Guidelines on the management of women with recurrent miscarriage. Association
of early pregnancy units. 2007. Available at: http://www.ptmp.pl/archives/apm/
13-4/APM134-guidelines-7-28.pdf.
18. Habayeb OM, Konje JC. The one-stop recurrent miscarriage clinic: an evaluation
of its effectiveness and outcome. Hum Reprod 2004;19(12):2952–8.
19. Musters AM, Taminiau-Bloem EF, van den Boogaard E, et al. Supportive care for
women with unexplained recurrent miscarriage: patients’ perspectives. Hum Reprod 2011;26(4):873–7.
20. Musters AM, Koot YE, van den Boogaard NM, et al. Supportive care for women
with recurrent miscarriage: a survey to quantify women’s preferences. Hum Reprod 2013;28(2):398–405.
21. Clifford K, Rai R, Regan L. Future pregnancy outcome in unexplained recurrent
first trimester miscarriage. Hum Reprod 1997;12(2):387–9.
22. Liddell HS, Pattison NS, Zanderigo A. Recurrent miscarriage–outcome after supportive care in early pregnancy. Aust N Z J Obstet Gynaecol 1991;31(4):320–2.
23. Lee C, Slade P. Miscarriage as a traumatic event: a review of the literature and
new implications for intervention. J Psychosom Res 1996;40(3):235–44.
24. Serrano F, Lima ML. Recurrent miscarriage: psychological and relational consequences for couples. Psychol Psychother 2006;79(Pt 4):585–94.
25. Geller PA, Kerns D, Klier CM. Anxiety following miscarriage and the subsequent
pregnancy: a review of the literature and future directions. J Psychosom Res
2004;56(1):35–45.
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26. Mevorach-Zussman N, Bolotin A, Shalev H, et al. Anxiety and deterioration of
quality of life factors associated with recurrent miscarriage in an observational
study. J Perinat Med 2012;40(5):495–501.
27. Klock SC, Chang G, Hiley A, et al. Psychological distress among women with
recurrent spontaneous abortion. Psychosomatics 1997;38(5):503–7.
28. Neugebauer R, Kline J, Shrout P, et al. Major depressive disorder in the 6 months
after miscarriage. JAMA 1997;277(5):383–8.
29. Craig M, Tata P, Regan L. Psychiatric morbidity among patients with recurrent
miscarriage. J Psychosom Obstet Gynaecol 2002;23(3):157–64.
30. Thapar AK, Thapar A. Psychological sequelae of miscarriage: a controlled study
using the general health questionnaire and the hospital anxiety and depression
scale. Br J Gen Pract 1992;42(356):94–6.
31. Conway K, Russell G. Couples’ grief and experience of support in the aftermath
of miscarriage. Br J Med Psychol 2000;73(Pt 4):531–45.
32. Beutel M, Willner H, Deckardt R, et al. Similarities and differences in couples’ grief
reactions following a miscarriage: results from a longitudinal study. J Psychosom
Res 1996;40(3):245–53.
33. Kagami M, Maruyama T, Koizumi T, et al. Psychological adjustment and psychosocial stress among Japanese couples with a history of recurrent pregnancy loss.
Hum Reprod 2012;27(3):787–94.
34. Sugiura-Ogasawara M, Suzuki S, Ozaki Y, et al. Frequency of recurrent spontaneous abortion and its influence on further marital relationship and illness: the
Okazaki Cohort Study in Japan. J Obstet Gynaecol Res 2013;39(1):126–31.
35. Stray-Pedersen B, Stray-Pedersen S. Etiologic factors and subsequent reproductive performance in 195 couples with a prior history of habitual abortion. Am J Obstet Gynecol 1984;148(2):140–6.
36. Fertl KI, Bergner A, Beyer R, et al. Levels and effects of different forms of anxiety
during pregnancy after a prior miscarriage. Eur J Obstet Gynecol Reprod Biol
2009;142(1):23–9.
155
U n e x p l a i n e d R e c u r re n t P re g n a n c y
Loss
Sotirios H. Saravelos,
MBBS,
Lesley Regan,
MBBS, MD, FRCOG*
KEYWORDS
Idiopathic Miscarriage Pregnancy loss Recurrent Unexplained
KEY POINTS
Women with unexplained recurrent pregnancy loss (RPL) represent a highly heterogeneous group of patients.
Some women will have suffered RPL attributable to chance alone, and will therefore have
a good future prognosis, whereas others will have a genuine pathologic condition that
cannot be identified by the current investigative protocols, and will have a comparatively
worse prognosis.
The definition used to diagnose RPL, specifically the number and type of previous miscarriages and maternal age, will significantly affect not only the incidence of women with RPL
but also the proportion of women with unexplained RPL.
Past studies have investigated systemic endocrine and immunologic mechanisms as potential causes for pregnancy loss in unexplained RPL, while exciting new work has
focused on spermatozoal, embryonic, and endometrial characteristics to explain the regulation of implantation and subsequent pregnancy loss.
In the clinical and research context, stratification of women with unexplained RPL according to whether they have a high probability of pathologic status will help select women who
are most appropriate for further investigation and potential future treatment.
THE IMPORTANCE OF THE DEFINITION
Recurrent pregnancy loss (RPL) is a heterogeneous condition that encompasses a
mixed cohort of women with different reproductive histories and a large range of
conditions.1 Unlike other diagnoses, the definition and diagnosis of RPL is a rather
arbitrary one, which is often the reason why different clinicians or bodies may use
different and interchangeable terms to characterize women with pregnancy losses,
for example:
Sporadic pregnancy loss (SPL): 1 miscarriage <24 weeks
Recurrent early pregnancy loss (REPL): 2 or more miscarriages <10 weeks
The authors have no conflicts of interest with regard to this work.
Department of Obstetrics and Gynaecology, St Mary’s Campus, Imperial College London, Mint
Wing, South Wharf Road, London W2 1PG, UK
* Corresponding author.
E-mail address: l.regan@imperial.ac.uk
Obstet Gynecol Clin N Am 41 (2014) 157–166
http://dx.doi.org/10.1016/j.ogc.2013.10.008
obgyn.theclinics.com
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158
Saravelos & Regan
Recurrent pregnancy loss (RPL): 2 or more miscarriages <24 weeks
Recurrent early miscarriage (REM): 3 or more consecutive miscarriages <10 weeks
Recurrent miscarriage (RM): 3 or more consecutive miscarriages <24 weeks
The main differences observed in varying terminologies used are (1) the number of
miscarriages and (2) the types of miscarriages (ie, early vs late). In the context of both
research and clinical practice, the number and types of miscarriages that are used in a
definition are extremely important, as they may result in different cohorts of patients
with different abnormalities, different prognoses, and different health care needs. As
a result, the definition used to diagnose RPL has a direct effect on the profile of women
who will eventually have a diagnosis of unexplained RPL.
Number of Miscarriages Suffered
If we accept that the average rate of sporadic miscarriage is approximately 15% in the
general population,2 then depending on the number of miscarriages that are required
to make the diagnosis of RPL, the theoretical incidence of the condition changes
(Table 1). For example, if 2 miscarriages are used for the definition of RPL, 2%
(0.152) or more of women will have the condition, whereas if 5 or more miscarriages
are used for the definition, as little as 0.01% (0.155) of women may have the condition.
Traditionally, the American Society for Reproductive Medicine (ASRM) has accepted 2
or more pregnancy losses as part of the definition,3 whereas the European Society for
Human Reproduction and Embryology (ESHRE) has used 3 or more pregnancy losses
in their definition.4 For the purpose of this article, both 2 and 3 miscarriages are discussed as part of the definition.
Types of Miscarriages Suffered
Another important element of the definition, which again would affect both the incidence and profile of patients diagnosed with RPL, is the type of pregnancy losses
included in the definition of RPL. The most important question is whether biochemical
pregnancy losses should be considered as part of the definition for RPL. Most bodies
make clear that only clinical pregnancies should be part of the definition, and the
ASRM is a good example because it states that pregnancy losses should include
only those that can be documented by ultrasonographic or histopathologic
Table 1
Theoretical incidence of recurrent pregnancy loss (RPL) according to the number of
miscarriages used in the definition
No. of Miscarriages Required
to Diagnose RPL
Incidence ‡
2
1/45
3
1/300
4
1/2000
5
1/13,000
6
1/90,000
7
1/600,000
8
1/4,000,000
Estimates based on a mean sporadic miscarriage rate of 15%.
Incidences calculated as I 5 mnumber of miscarriages (where m 5 sporadic miscarriage rate of 15%).
Incidences may be underestimated, as the true incidence of RPL is thought to be more than the
theoretical incidence.
Unexplained Recurrent Pregnancy Loss
examination.3 The reason for this is that biochemical pregnancy losses have been
shown to be very common in the general population, with almost 60% to 80% of pregnancies thought to end in an early preclinical loss.5,6 Despite this, clinicians may still
find it difficult to exclude these pregnancies from the definition of RPL, particularly if
women have used sensitive over-the-counter tests to identify early pregnancies and
are subsequently anxious for investigations following repeated biochemical losses.
However, if put into context, it can be estimated that almost 20% (0.63) of women in
the general population may experience 3 biochemical pregnancy losses attributable to
chance alone,7 most of which will not need investigating.
Maternal Age
Most definitions of RPL will not include the age of the woman. However, maternal age
is perhaps the single most important determinant of miscarriage in the general and the
RPL populations,2,8 which is invariably a result of oocyte and embryonic aneuploidy.9
As a result, the age of the women will affect the incidence of the condition (Table 2).
For example, the theoretical incidence of RPL (2 pregnancy losses) in women younger
than 25 years is approximately 1.2% (SPL rate of 0.112), whereas for women of
45 years or older it may exceed 50% (SPL rate of 0.752).
INCIDENCE
Unexplained Recurrent Pregnancy Loss
Although the exact incidence of RPL has never been reliably determined, most investigators would agree that the overall incidence of RPL (2 or more pregnancy losses) is
approximately 3%, whereas that of RM (3 or more miscarriages) is approximately 1%
of the population.10 From these data, it is deduced that approximately 50% of women
will suffer from unexplained RPL.11,12 However, just as the factors mentioned previously (ie, number of miscarriages, types of miscarriages, and maternal age) will affect
the incidence of RPL, they will also affect the proportion of women that will be diagnosed with unexplained RPL. For example, if women older than 40 years are selected,
not only will there be a higher incidence of women diagnosed with RPL (at least 25%),
but the majority, approximately 65%, will have suffered miscarriages resulting from
embryonic chromosomal anomalies, most commonly aneuploidy,13 and therefore
very few may be truly unexplained. In fact, they will be healthy women with recurrent
SPL with no additional abnormality or, otherwise, women with RPL attributable to
chance alone. Paradoxically, if there are no cytogenetics available when the patient
Table 2
Theoretical incidence of RPL (2 pregnancy losses) according to maternal age
Maternal Age
Incidence of RPL ‡
20
1/85
25
1/70
30
1/45
35
1/16
40
1/4
45
1/2
Estimates based on a sporadic miscarriage rates according to maternal age.
Incidences calculated as I 5 m2 (where m 5 sporadic miscarriage rates for age).
Incidences may be underestimated, as the true incidence of RPL is thought to be more than the
theoretical incidence.
159
160
Saravelos & Regan
presents to the clinic (which often is the case), most will be diagnosed as having unexplained RPL, as these patients are unlikely to have any abnormalities identified on
routine testing. This situation shows the importance of distinguishing between healthy
women with RPL attributable to chance alone (secondary to aneuploidy) and women
with genuine unexplained RPL that may have a treatable disorder other than
aneuploidy.
Recurrent Pregnancy Loss Attributable to Chance
In any cohort of women with RPL, a proportion of women will have suffered sporadic
RPL that can be attributed to chance alone.7,14 As mentioned previously, these
women will not have any additional abnormality, their routine investigations will be
negative, and they will invariably be diagnosed as having unexplained RPL. It is therefore very important to distinguish between women with sporadic RPL attributable to
chance and women with genuine unexplained RPL as it may be only the latter that
require investigation and treatment.
To estimate the proportion of women with RPL who have suffered from RPL that is
due to chance alone, the incidence of SPL in the general population needs to be identified2 followed by the rates of recurrent SPL (occurring from chance alone) using the
assumption that if SPL rate 5 m, recurrent SPL rate 5 mn, where n 5 number of miscarriages (Table 3). When performing this analysis for women aged 30 to 35 years, it
is shown that 2.25% will have suffered 2 SPL resulting from chance, whereas 0.34%
will have suffered 3 SPL attributable to chance alone. Given that the total incidence of
RPL and RM is thought to be 1% and 3%, respectively, it can be assumed that up to
75% (2.25/3) of women with RPL may have suffered 2 RPL attributable to chance
alone, whereas up to 35% (0.34/1) may have suffered 3 RPL that is due to chance
alone.
THE CAUSES OF UNEXPLAINED RECURRENT PREGNANCY LOSS
The Factor of Chance
As already mentioned, a significant number of women will have suffered RPL because
of chance alone and will not have any identifiable abnormality other than embryonic
aneuploidy, which may not have been tested before the referral to a specialist clinic.
These patients are healthy women who have been unlucky in their pursuit of a pregnancy, and will be diagnosed as having unexplained RPL because their investigations
will be invariably normal. These women are also those with a very good prognosis in
their future pregnancy without the need for surgical or pharmacologic intervention.
Table 3
Incidence of RPL occurring by chance for women with 1, 2, and 3 miscarriages
Recurrent Pregnancy Loss Rates (Occurring by Chance) (%)
Age (y)
1 Miscarriage
2 Miscarriages
3 Miscarriages
20–24
11
1.21
0.13
25–29
12
1.44
0.17
30–34
15
2.25
0.34
35–39
25
6.25
1.56
Data from Saravelos SH, Li TC. Unexplained recurrent miscarriage: how can we explain it? Hum Rep
2012;27(7):1882–6; and Nybo Andersen AM, Wohlfahrt J, Christens P, et al. Maternal age and fetal
loss: population-based register linkage study. BMJ 2000;320(7251):1708–12.
Unexplained Recurrent Pregnancy Loss
This proposition is supported by well-conducted randomized controlled trials (RCTs)
and meta-analyses, which have shown that treatment such as aspirin, heparin, and
intravenous immunoglobulin does not improve pregnancy outcomes in women with
unexplained RPL.15,16
Of course, not all women with unexplained RPL will have suffered their pregnancy losses attributable to chance alone, and a certain proportion will have pathologic conditions other than embryonic aneuploidy that will not be detected by the
current investigation protocols. These women, typically younger, will go on to suffer higher order of miscarriages (4, 5, or more) and are the most challenging to
manage.
The Egg
Although it is accepted that aneuploidy is the main cause for pregnancy loss in women
with increased maternal age, it has been speculated that some women with unexplained RPL may suffer from premature ovarian aging, leading to reduced oocyte quality and quantity. Although oocyte quantity and quality cannot be easily assessed, one
group compared basal follicle-stimulating hormone (FSH) in women with unexplained
RPL and in controls as an indirect means of assessing for premature ovarian aging and
decline in oocyte quality.17 Their results showed comparable basal FSH levels for both
groups across all ages up to 40 years.
Another group reported on oocyte donations of 8 couples with unexplained RPL
who had poor response to ovarian hyperstimulation.18 This study is interesting, as
oocyte donation could theoretically reduce the risk of pregnancy loss in women
suffering from RPL attributable to oocyte and embryonic aneuploidy. The investigators
reported a rate of 11.1% pregnancy loss in these 8 cycles, and questioned whether the
oocyte, rather than maternal and paternal factors, is the origin of RPL. Unfortunately,
although these preliminary findings are exciting, there is an urgent need for further
controlled follow-up studies.
The Sperm
The role of the sperm in unexplained RPL remains controversial, with varying original
reports on factors such as Y-chromosome microdeletions, sperm oxidative stress,
sperm DNA fragmentation, sperm concentration, morphology, and function.19 More
recently, a systematic review and meta-analysis reported that DNA fragmentation
was indeed significantly associated with miscarriage, and concluded that using
methods to select sperm without DNA damage may reduce miscarriage in assisted
conception treatment.20 The implications of these findings for the unexplained RPL
population are still open to debate.
The Embryo
Similar to reducing the risk of chromosomal abnormalities by focusing on the egg
and sperm, it has been thought that artificial reproductive technology (ART), and
specifically preimplantation genetic screening (PGS) of the embryo for aneuploidy
in women with unexplained RPL, may improve the prognosis for such women. A systematic review that was performed to assess this question concluded that although
the miscarriage rates following PGS may be slightly lower, the lack of RCTs, the
invasiveness of ART, and the relatively good prognosis of women with unexplained
RPL and natural conception renders this treatment inappropriate until further robust
data are available.21 This view is also held by the ESHRE PGD consortium22 and the
practice committees of the ASRM and the Society for Assisted Reproductive
Technology.23
161
162
Saravelos & Regan
The Endometrium
Other than looking at the embryo itself as a cause for unexplained RPL, another focus
in the recent years has been the endometrium, and its ability to distinguish between
good-quality and poor-quality embryos.24 A preliminary study showed that women
with RPL expressed increased levels of proimplantation cytokines, which rendered
approximately 40% of them superfertile.25 The investigators hypothesized that this
superfertility disables the natural selection of healthy embryos and allows implantation
of poor-quality embryos, which subsequently inevitably leads to pregnancy loss. A
subsequent study attempted to investigate this further by looking at endometrial
stromal cell migratory activity in response to high-quality and low-quality human embryos.26 In women with RPL, the migratory activity did not differ between high-quality
and low-quality embryos, whereas in the fertile control group the migratory activity
was inhibited in low-quality embryos in comparison with high-quality embryos. It is
hoped that future studies focusing on the mechanisms by which low-quality embryos
inhibit human stromal cell migratory activity will provide further insight into the
embryo-endometrial interactions that control implantation and ultimately determine
the pregnancy outcome.
Systemic Factors
Other than the embryo-endometrial interactions, a plethora of research has focused
on systemic conditions as a possible cause of unexplained RPL. Until these conditions
are proved to have a causal effect, most women with these abnormalities may still be
diagnosed as having unexplained RPL. Thyroid abnormalities, and particularly thyroid
antibodies, have been associated with miscarriage in a recent meta-analysis of evidence,27 although the treatment with thyroxine has yet to be of proven benefit in the
context of unexplained RPL.28 Polycystic ovary syndrome, insulin resistance, and
hyperadrogenemia have all been linked with unexplained RPL,29 although treatment
with insulin-sensitizing agents such as metformin to reduce pregnancy loss remains
debatable. A systematic review and meta-analysis showed preconception metformin
did not reduce rates of pregnancy loss in women with infertility, whereas small retrospective studies have shown reductions in rates of pregnancy loss in women with previous miscarriages.30,31 Abnormal immunologic reactions have also been extensively
examined with regard to unexplained RPL. Peripheral and uterine natural killer cells
have been associated with unexplained RPL in some case-control studies; however,
the current evidence does not justify their routine use as prognostic indicators or their
subsequent treatment with immunotherapy.32 Immunologic reaction to male-specific
minor histocompatibility H-Y antigens has also been hypothesized as a cause of pregnancy loss in women with secondary unexplained RPL following the birth of a boy.33
Two studies have indirectly supported this hypothesis by showing that male sex of the
first-born child is a strong negative prognostic factor in women with secondary
RPL,34,35 emphasizing the need for further research into this area.
PROGNOSIS OF UNEXPLAINED RECURRENT PREGNANCY LOSS
Traditional View
Traditionally, women with unexplained RPL have been thought to have an excellent
prognosis in subsequent pregnancies without the need for any surgical or pharmacologic intervention. This idea has been based predominantly on 3 small nonrandomized trials that have shown reduction in rates of pregnancy loss of up to 50% in
women who received psychological supportive care in a dedicated clinic, in comparison with patients who either did not return to the clinic or were looked after in
Unexplained Recurrent Pregnancy Loss
a routine antenatal setting.12,36 The conclusions drawn from these trials have led to
the globally recognized concept of tender love and care (TLC) in the setting of unexplained RPL. However, there were serious limitations in these trials. The first study by
the Stray-Pedersens36 was performed in 1984 at a time when routine investigations
such as antiphospholipid screening did not exist. Furthermore, the control group
consisted of 24 women who attended a local antenatal care clinic geographically
further away from the investigators’ dedicated clinic. The second study by Liddell
and colleagues37 in 1991 reported on only 9 women who did not receive psychological supportive care, whereas in the study by Clifford and colleagues12 in 1997, the
control group consisted of 41 women who failed to return to the clinic and had to
be contacted by phone or letter for their future outcomes to be established. Despite
the limitations of these studies, the concept of psychological supportive care/TLC
has been widely accepted and incorporated into various national guidelines.38,39
However, although TLC broadly consists of serial ultrasonographic scans to confirm
viability along with access to specialist counseling, historically it has not been a welldefined entity, and therefore it has been difficult to examine the mechanism through
which it operates.40 A recent survey has attempted to characterize women’s preferences for supportive care, and has identified needs such as frequency of ultrasonograms, number of doctors, type of soft skills, and aftercare that women find the most
reassuring.41 It is hoped that future controlled studies will be able to quantify these
variables and assess their effect on the pregnancy outcome of women with unexplained RPL.
Novel Views
More recently, it has been proposed that the favorable prognosis in women with
unexplained RPL may not be due to psychological supportive care/TLC.7 It was proposed that because a significant proportion of women with unexplained RPL will be
healthy women that have suffered RPL attributable to chance, their prognosis without
any intervention will be favorable and similar to that of women in the general population. In analyzing 844 women with untreated unexplained RPL, it was found that the
subsequent pregnancy loss of 14% to 26% was almost identical to the 12% to
25% rate of pregnancy loss in the general population for women aged 25 to 39 years.
It is therefore concluded that although psychological supportive care/TLC is a
commendable and positive experience for women with unexplained RPL, it is unlikely
to be the reason why their prognosis in subsequent pregnancies is good.
STRATIFICATION OF WOMEN WITH UNEXPLAINED RECURRENT PREGNANCY LOSS
Although most women with unexplained RPL will have favorable outcomes, a proportion will continue to suffer pregnancy losses, which would imply that they have not
suffered their pregnancy losses because of chance and have a genuinely unidentified
pathologic cause. Other than the great difficulty the women will have in coming to
terms with the condition, these women will be the most difficult to manage from a clinical point of view as there will be no evidence-based treatment to offer. However, such
women benefit most from enrolling in well-designed trials investigating novel disorders
and treatments.
The key is therefore to identify and distinguish between women with unexplained
RPL who have suffered their pregnancy losses by chance alone and women with unexplained RPL and genuine abnormality. It has recently been proposed that these
groups can be classified as having type I and type II unexplained RPL, respectively.7
The characteristics of these 2 groups of women are summarized in Table 4.
163
164
Saravelos & Regan
Table 4
Characteristics of women with type I and type II unexplained RPL
Pregnancy Losses
Age
Number
Types
Likely Pathology
Type I
Older
<3
Includes biochemical
Abnormal karyotype of conceptus
Type II
Younger
>3
Clinical only
Remains unidentifiable
Data from Saravelos SH, Li TC. Unexplained recurrent miscarriage: how can we explain it? Hum Rep
2012;27(7):1885.
SUMMARY
Women with unexplained RPL represent a highly heterogeneous group. Some women
will have suffered RPL attributable to chance alone, whereas others will have genuine
pathologic status that cannot be identified by the current investigative protocols. The
definition used to diagnose RPL will significantly affect not only the incidence of
women with RPL but also the proportion of women with unexplained RPL. As a result,
if women with 2 pregnancy losses and biochemical pregnancy losses are included in
the definition, most women may be diagnosed with unexplained RPL and may be
entirely healthy. Conversely, if 3 pregnancy losses and clinical pregnancy losses alone
are included in the definition, less than one-third of women diagnosed will have suffered RPL because of chance, and therefore the cohort will contain more women
with genuine abnormality. Past studies have investigated systemic endocrine and
immunologic mechanisms as potential causes of pregnancy loss in unexplained
RPL, whereas recent work has focused on spermatozoal, embryonic, and endometrial
characteristics to explain the regulation of implantation and subsequent pregnancy
loss. Future stratification of women with unexplained RPL, both in the clinical and
research context, according to whether they have a high probability of pathologic status, will help select women who are more appropriate for further investigation and
potential future treatment.
ACKNOWLEDGMENTS
The authors wish to acknowledge the support from the National Institute for Health
Research Imperial Biomedical Research Centre.
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18. Remohi J, Gallardo E, Levy M, et al. Oocyte donation in women with recurrent
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19. Vissenberg R, Goddijn M. Is there a role for assisted reproductive technology in
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21. Musters AM, Repping S, Korevaar JC, et al. Pregnancy outcome after preimplantation genetic screening or natural conception in couples with unexplained recurrent miscarriage: a systematic review of the best available evidence. Fertil Steril
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22. Thornhill AR, deDie-Smulders CE, Geraedts JP, et al. ESHRE PGD Consortium
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I ndex
Note: Page numbers of article titles are in boldface type.
A
Acquired thrombophilias, 137
Adhesion(s)
intrauterine
RPL related to, 6
RPL related to, 69–73
causes of, 69–72
characteristics of, 69
classification of, 69
first-trimester pregnancy loss due to, 72
prevalence of, 72
treatment of, 72–73
Age
maternal
as factor in unexplained RPL, 159
Alcohol consumption
RPL related to, 13
Amniocentesis
in reproductive medicine, 45–46
Aneuploidy
basics of, 44–45
recurrent
RPL related to, 12
Antenatal genetic testing
in reproductive medicine, 43–46
amniocentesis, 45–46
aneuploidy, 44–45
cell-free fetal DNA evaluation, 46
CVS, 45–46
Antibody(ies)
antiphospholipid. See Antiphospholipid antibody(ies) (aPLs)
Antinuclear antibodies
RPL related to, 10–11
Antiphospholipid antibody(ies) (aPLs)
thrombosis and, 121–122
Antiphospholipid antibody syndrome (APS), 113–132
defective placentation and, 122
diagnosis of, 114–118
clinical criteria in, 114–116
laboratory criteria in, 117–118
introduction, 113–114
lifelong consequences of, 126
Obstet Gynecol Clin N Am 41 (2014) 167–176
http://dx.doi.org/10.1016/S0889-8545(13)00123-X
0889-8545/14/$ – see front matter ª 2014 Elsevier Inc. All rights reserved.
obgyn.theclinics.com
168
Index
Antiphospholipid (continued )
local inflammatory events and, 122–123
management of
heparin in, 123
in pregnancy, 123–125
antepartum surveillance, 125
overview of, 123–124
unfractionated heparin vs. LMWH, 124–125
MTL related to, 90
treatment of, 90
obstetric complications of, 118–120
pathophysiology of, 120–123
postpregnancy considerations, 126
RPL related to, 9–10, 118–120
severe placental insufficiency related to, 120
Antithrombin deficiency
inherited thrombophilias related to, 136–137
aPLs. See Antiphospholipid antibody(ies) (aPLs)
APS. See Antiphospholipid antibody syndrome (APS)
Arcuate uterus, 61
metroplasty for, 68
B
Bicornuate uterus, 59, 60
metroplasty for, 68
C
Caffeine intake
RPL related to, 13
Cell-free fetal DNA evaluation
in reproductive medicine, 46
Cervical cerclage
for RPL related to uterine anomalies, 68–69
Cervical occlusion
in cervical weakness–related MTL management, 95–96
Cervical weakness
MTL related to, 93–98. See also Mid-trimester pregnancy loss (MTL), cervical weakness
and
Cervix
incompetent
RPL related to, 7
Chorionic villus sampling (CVS)
in reproductive medicine, 45–46
Chromosomal disorders
parental
RPL related to, 11–12
Cigarette smoking
RPL related to, 13
Congenital malformations
Index
RPL related to, 5–6
CVS. See Chorionic villus sampling (CVS)
D
DES. See Diethylstilbestrol (DES)
Didelphic uterus, 59, 60
metroplasty for, 68
Diethylstilbestrol (DES) drug-related uterus, 61
E
Embryo(s)
euploid
developmental errors in
RPL related to, 12
Endocrine system
in RPL, 103–112. See also Recurrent pregnancy loss (RPL), endocrine basis for
Environmental factors
uterine anomalies related to
RPL due to, 61
Environmental toxins
RPL related to, 12–13
Euploid embryos
developmental errors in
RPL related to, 12
F
Factor V Leiden
inherited thrombophilias related to, 135–136
Fibroid(s)
RPL related to, 73–76
causes of, 74
characteristics of, 73–74
classification of, 73–74
first-trimester pregnancy loss due to, 75
prevalence of, 74–75
treatment of, 75–76
First-trimester pregnancy loss
adhesions and, 72
fibroids and, 75
polyps and, 77
uterine anomalies and, 64–67
G
Genetic(s)
in reproductive medicine, 41–55
evolving role of, 41–55
genetic analysis following fetal demise, 52
169
170
Index
Genetic(s) (continued)
introduction, 42
preconception genetic testing, 42–43
preimplantation genetic testing, 46–52
RPL related to, 11–12
uterine anomalies related to
RPL due to, 62
Genetic testing
antenatal, 43–46
preconception, 42–43
Glucose metabolism
abnormal
RPL related to, 8
H
Heparin
in APS management, 123
low-molecular-weight
in APS management in pregnancy
vs. unfractionated heparin, 124–125
unfractionated
in APS management in pregnancy
vs. LMWH, 124–125
Hyperprolactinemia
RPL related to, 8
Hypothyroidism
untreated
RPL related to, 8
I
Immunologic disorders
RPL related to, 9
Immunotherapy
RPL related to, 10
Incompetent cervix
RPL related to, 7
Infection(s)
MTL related to, 90–92
Inherited thrombophilias, 133–144
antithrombin deficiency and, 136–137
combined defects, 137
discussion, 140–141
factor V Leiden and, 135–136
future directions in, 141–142
introduction, 133–134
MTHFR and, 137
overview of, 134–135
protein C deficiency and, 136
protein S deficiency and, 136
prothrombin and, 136
Index
research related to, 141–142
testing criteria for, 139–140
treatment of, 138–141
physician practice patterns in, 139–140
Intrauterine adhesions
RPL related to, 6
Intrauterine masses
RPL related to, 6–7
Ionizing radiation
RPL related to, 13
L
Lifestyle issues
RPL related to, 12–13
LMWH. See Low-molecular-weight heparin (LMWH)
Low-molecular-weight heparin (LMWH)
in APS management in pregnancy
vs. unfractionated heparin, 124–125
Luteal phase defect
RPL related to, 104–105
Luteal phase deficiency
RPL related to, 7
M
Mass(es)
intrauterine
RPL related to, 6–7
Maternal age
as factor in unexplained RPL, 159
Methylene tetrahydrofolate reductase (MTHFR)
inherited thrombophilias related to, 137
Metroplasty
for RPL-related to uterine anomalies, 68
Microbiologic agents
RPL related to, 11
Mid-trimester pregnancy loss (MTL), 87–102
APS and, 90
cervical weakness and, 93–98
described, 93–94
management of, 94–98
cervical occlusion in, 95–96
progesterone in, 94–95
TAC in, 96–98
TVC in, 95
ultrasound assessment in, 94
classification of, 87
defined, 87
infection and, 90–92
introduction, 87–88
171
172
Index
Mid-trimester (continued )
pathology associated with, 90
screening protocol for, 88–90
treatment of, 90
uterine anomalies and, 92–93
Miscarriage(s)
causes of
mechanisms of, 67
described, 145
recurrent. See Recurrent miscarriage(s) (RMs)
unexplained RPL and, 158
MTHFR. See Methylene tetrahydrofolate reductase (MTHFR)
MTL. See Mid-trimester pregnancy loss (MTL)
Müllerian duct(s)
differentiation of
defects in, 61
fusion of
defects in, 59, 60
1
defects in formation of, 59
O
Obesity
RPL related to, 13
Ovarian reserve
diminished
RPL related to, 8–9
P
Parental chromosomal disorders
RPL related to, 11–12
PCOS. See Polycystic ovarian syndrome (PCOS)
PGS. See Preimplantation genetic screening (PGS)
Placental insufficiency
severe
RPL related to, 120
Polycystic ovarian syndrome (PCOS)
RPL related to, 108–109
Polyp(s)
RPL related to, 77–78
Preconception genetic testing
in reproductive medicine, 42–43
Pregnancy
APS in
management of, 123–125. See also Antiphospholipid antibody syndrome (APS),
management of, in pregnancy
Pregnancy loss
causes of
mechanisms of, 67
Index
defined, 2
early. See also Recurrent pregnancy loss (RPL)
management of, 1–18
introduction, 1–2
first-trimester
adhesions and, 72
fibroids and, 75
polyps and, 77
uterine anomalies and, 64–67
mid-trimester, 87–102. See also Mid-trimester pregnancy loss (MTL)
Preimplantation genetic diagnosis
in reproductive medicine, 47–48
Preimplantation genetic screening (PGS)
in reproductive medicine, 48–51
clinical application of, 51
limitations of, 51–52
Preimplantation genetic testing
in reproductive medicine, 46–52
diagnosis-related, 47–48
PGS, 48–51
in RPL detection, 12
Progesterone
in cervical weakness–related MTL management, 94–95
Protein C deficiency
inherited thrombophilias related to, 136
Protein S deficiency
inherited thrombophilias related to, 136
Prothrombin
inherited thrombophilias related to, 136
R
Radiation
ionizing
RPL related to, 13
Randomized controlled trials (RCTs)
in RPL research, 33–35
RCTs. See Randomized controlled trials (RCTs)
Recurrent aneuploidy
RPL related to, 12
Recurrent miscarriage(s) (RMs)
described, 145
guidelines related to, 146–147
Recurrent miscarriage clinics, 145–155
doctor preferences, 150–151
introduction, 145–146
logistic requirements for, 147–150
equipment, 148–149
laboratory services, 149
location, 147
record keeping, 149
173
174
Index
Recurrent (continued )
rooms, 147
staffing, 147
one-stop, 149–150
patient preferences, 152–153
recommendations, 153
Recurrent pregnancy loss (RPL)
APS and, 9–10, 118–120
causes of, 2–3, 57
anatomic, 5–7
autoimmune/thrombotic factors, 9–11
endocrinologic, 7–9
environmental toxins, 12–13
genetic factors, 11–12
lifestyle issues, 12–13
chance as factor in, 160
defined, 2, 157–158
controversies related to, 20–21
diagnosis of, 3–5
endocrine basis for, 103–112
luteal phase defect, 104–105
PCOS, 108–109
thyroid disease, 105–108
introduction, 1–2
outcome of, 13–14
prevalence of, 2
research methodology in, 19–39
case-control studies, 22–29
flaws in estimating risk factors, 24–28
flaws in sampling of patients and controls, 22–24
interpretation, 29
lack of protocol data or priory hypothesis, 28–29
multiple testing, 29
cohort studies, 29–32
cohorts estimating live births per time unit, 32
concurrent vs. nonconcurrent cohorts, 30
nonrandom misclassification, 30–32
introduction, 19–20
research studies, 21–22
treatment trials, 32–36
historical controls, 32–33
RCTs, 33–35
systematic reviews, 35–36
risk factors for, 2
treatment of, 3–5
unexplained, 157–166. See also Unexplained recurrent pregnancy loss (RPL)
uterine anomalies and, 57–86. See also Uterine anomalies, RPL related to
Reproductive medicine
genetics in
evolving role of, 41–55. See also Genetic(s), in reproductive medicine
RM. See Recurrent miscarriage(s) (RMs)
Index
S
Septate uterus, 61
metroplasty for, 68
Septum
regression of
defects in, 61
Severe placental insufficiency
RPL related to, 120
Single-gene disorders
in reproductive medicine, 47–48
Smoking
RPL related to, 13
Structural chromosome aberrations
in reproductive medicine, 48
T
TAC. See Transabdominal cerclage (TAC)
Thrombophilia(s)
acquired, 137
inherited, 133–144. See also Inherited thrombophilias
Thrombotic disorders
RPL related to, 11
Thyroid disease
RPL related to, 105–108
Toxin(s)
environmental
RPL related to, 12–13
Transabdominal cerclage (TAC)
in cervical weakness–related MTL management, 96–98
research evidence for, 96–98
Transvaginal cervical cerclage (TVC)
in cervical weakness–related MTL management, 95
TVC. See Transvaginal cervical cerclage (TVC)
U
Ultrasound
in cervical weakness–related MTL management, 94
Unexplained recurrent pregnancy loss (RPL), 157–166
causes of, 160–162
defined, 157–158
incidence of, 159–160
maternal age as factor in, 159
miscarriages suffered due to, 158
prevalence of, 160
prognosis of, 162–163
stratification of women with, 163–164
Unfractionated heparin
in APS management in pregnancy
vs. LMWH, 124–125
175
176
Index
Unicornuate uterus, 59
metroplasty for, 68
Uterine anomalies
congenital, 59–61
classification and embryology of, 59–61
MTL related to, 92–93
RPL related to, 57–86
acquired, 69–78
adhesions, 69–73
causes of, 61–62
congenital, 64–67
diagnosis of
imaging in, 58
fibroids, 73–76
introduction, 57
polyps, 77–78
prevalence of, 62–64
treatment of, 68–69
Uterus
arcuate, 61
metroplasty for, 68
bicornuate, 59, 60
metroplasty for, 68
DES drug-related, 61
didelphic, 59, 60
metroplasty for, 68
embryology of, 58
septate, 61
metroplasty for, 68
unicornuate, 59
metroplasty for, 68
Recurrent First Trimester Pregnancy Loss
Contributors
CONSULTING EDITOR
WILLIAM F. RAYBURN, MD, MBA
Professor and Chair, Department of Obstetrics and Gynecology; Associate Dean,
Continuing Medical Education and Professional Development, University of New Mexico
School of Medicine, Albuquerque, New Mexico
EDITOR
WILLIAM H. KUTTEH, MD, PhD, HCLD
Clinical Professor, Department of Obstetrics and Gynecology, Division of Reproductive
Endocrinology and Infertility, Vanderbilt University School of Medicine, Nashville;
Consulting Gynecologist, Department of Surgery, St. Jude Children’s Research Hospital,
Memphis; Director, Recurrent Pregnancy Loss Center, Managing Partner, Fertility
Associates of Memphis, Memphis, Tennessee
AUTHORS
PAUL R. BREZINA, MD, MBA
Assistant Clinical Professor, Department of Obstetrics and Gynecology, Division of
Reproductive Endocrinology and Infertility, Vanderbilt University School of Medicine,
Nashville; Consulting Gynecologist, Department of Surgery, St. Jude Children’s Research
Hospital, Memphis; Director of Reproductive Genetics, Fertility Associates of Memphis,
Memphis, Tennessee
OLE B. CHRISTIANSEN, MD, DMSc
Professor, Consultant in Department of Obstetrics and Gynecology, Fertility Clinic 4071,
Copenhagen University Hospital, Copenhagen; Department of Obstetrics and
Gynecology, Aalborg University Hospital, Aalborg, Denmark
WILLIAM B. DAVENPORT, MD
Department of Obstetrics and Gynecology, University of Vermont, Burlington, Vermont
FEROZA DAWOOD, MBChB, MRCOG, MD
Consultant in Obstetrics and Gynaecology, Department of Obstetrics, Liverpool Women’s
Hospital, Liverpool, United Kingdom
ROY G. FARQUHARSON, MD, FRCOG
Consultant in Gynaecology, Liverpool Women’s Hospital, Liverpool, United Kingdom
MARIËTTE GODDIJN, MD, PhD
Department of Obstetrics and Gynaecology, Center for Reproductive Medicine, Academic
Medical Center, Amsterdam, The Netherlands
CANDACE D. HINOTE, MD
MidSouth OB GYN, Memphis, Tennessee
iv
Contributors
CAROLYN R. JASLOW, PhD
Department of Biology, Rhodes College, Memphis, Tennessee
RAYMOND W. KE, MD, HCLD
Clinical Professor of Obstetrics and Gynecology, Vanderbilt University, Nashville; Chief,
Assisted Reproduction, Fertility Associates of Memphis, Memphis, Tennessee
WILLIAM G. KEARNS, PhD
Associate Professor, Department of Gynecology and Obstetrics, Johns Hopkins Medical
Institutions, Baltimore; Director, The Center for Preimplantation Genetics, LabCorp,
Rockville, Maryland
WILLIAM H. KUTTEH, MD, PhD, HCLD
Clinical Professor, Department of Obstetrics and Gynecology, Division of Reproductive
Endocrinology and Infertility, Vanderbilt University School of Medicine, Nashville;
Consulting Gynecologist, Department of Surgery, St. Jude Children’s Research Hospital,
Memphis; Director, Recurrent Pregnancy Loss Center, Managing Partner, Fertility
Associates of Memphis, Memphis, Tennessee
KELLY M. MCNAMEE, MBChB(Hon)
Obstetric and Gynaecology Specialist Trainee, Department of Obstetrics, Liverpool
Women’s Hospital, Liverpool, United Kingdom
LESLEY REGAN, MBBS, MD, FRCOG
Professor, Department of Obstetrics and Gynaecology, St Mary’s Campus, Imperial
College London, London, United Kingdom
SOTIRIOS H. SARAVELOS, MBBS
Department of Obstetrics and Gynaecology, St Mary’s Campus, Imperial College London,
London, United Kingdom
M.M.J. VAN DEN BERG, MD
Department of Obstetrics and Gynaecology, Center for Reproductive Medicine,
Academic Medical Center, Amsterdam, The Netherlands
ROSA VISSENBERG, MD
Department of Obstetrics and Gynaecology, Center for Reproductive Medicine,
Academic Medical Center, Amsterdam, The Netherlands
viii
Recurrent First Trimester Pregnancy Loss
OBSTETRICS AND GYNECOLOGY CLINICS
FORTHCOMING ISSUES
RECENT ISSUES
June 2014
Addiction Disorders in Pregnancy
William Rayburn and Hillary Connery,
Editors
December 2013
Procedures in the Office Setting
Tony Ogburn and Besty Taylor, Editors
September 2014
Gynecologic Pelvic Pain
Mary McLennan, Editor
December 2014
Infectious Diseases in Pregnancy
Geeta Swamy, Editor
September 2013
Breast Disorders
Victoria L. Green and Patrice M. Weiss,
Editors
June 2013
HPV, Colposcopy, and Prevention of
Squamous Anogenital Tract Malignancy
Alan G. Waxman and Maria Lina Diaz,
Editors
ISSUE OF RELATED INTEREST
Clinics in Perinatology, September 2011
Prematurity: Art and Science
Alan R. Fleischman and Jay D. Iams, Editors
NOW AVAILABLE FOR YOUR iPhone and iPad
Recurrent First Trimester Pregnancy Loss
Foreword
William F. Rayburn, MD, MBA
Consulting Editor
This unique issue of the Obstetrics and Gynecology Clinics of North America, guest
edited by Dr. William Kutteh, deals with an update on the evaluation and treatment
for recurrent pregnancy loss. Recurrent pregnancy loss typically is defined as two or
more consecutive pregnancy losses and occurs in approximately 1% of women attempting to bear a child. Recurrent early pregnancy loss is often heterogeneous in
origin and is frustrating for the couple, the patients, and clinicians.
For patients with recurrent pregnancy loss, it is reasonable to offer a basic evaluation. As reviewed nicely in this text, the evaluation of women with recurrent pregnancy
loss should consider the following factors: antiphospholipid syndrome, endocrine or
metabolic imbalances, exposure to toxins and drugs, genetic abnormalities, immunologic disorders, pelvic infections, thrombophilia, and uterine abnormalities. Laboratory
studies should include testing for lupus anticoagulant, anticardiolipin antibodies, and
microarray genetic testing. Those couples affected by chromosomal abnormalities
should be counseled about the risk of recurring abortion and offered prenatal genetic
studies as well as considered for newer assisted reproductive technologies for future
pregnancies. Cultures for bacteria or viruses and tests for glucose intolerance, antibodies to infectious agents, antinuclear antibodies, antithyroid antibodies, paternal
human leukocyte antigen status, or maternal antipaternal antibodies are generally
not beneficial.
The authors describe how corrective surgery for uterine defects or a presumed
incompetent cervix may be reasonable when such defects appear to interfere with implantation, pregnancy growth, or pregnancy retention. The role of luteal phase defect is
controversial, and supplementation with progesterone is of unproven efficacy. Immunoglobulin and paternal leukocyte therapies are not effective in preventing recurrent
pregnancy loss.
Nearly half of couples who complete this evaluation will not have an identifiable
cause. Informative and supportive counseling appears to play an important role and
may lead to the best pregnancy outcomes. Couples with unexplained recurrent pregnancy loss should be counseled regarding the potential for successful pregnancy
without treatment. The risk of recurrent abortion after two successive losses remains
stable with future pregnancies.
Obstet Gynecol Clin N Am 41 (2014) ix–x
http://dx.doi.org/10.1016/j.ogc.2013.11.001
obgyn.theclinics.com
0889-8545/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
x
Foreword
Contributors to this issue represent some of the field’s most dedicated clinicians
and investigators, most of whom have spent their entire careers working with couples
affected by repeated losses. I am grateful to Dr. Kutteh and these dedicated individuals for their willingness to contribute to this special issue.
William F. Rayburn, MD, MBA
Professor and Chair
Department of Obstetrics and Gynecology
Associate Dean
Continuing Medical Education and Professional Development
University of New Mexico School of Medicine
MSC10 5580, 1 University of New Mexico
Albuquerque, NM 87131-0001, USA
E-mail address:
wrayburn@salud.unm.edu
Recurrent First Trimester Pregnancy Loss
Preface
Recurrent Pregnancy Loss
William H. Kutteh, MD, PhD, HCLD
Editor
This issue of the Obstetrics and Gynecology Clinics of North America focuses on the
advances in the evaluation and management of recurrent pregnancy loss (RPL) that
have emerged within the last few years. Although spontaneous pregnancy loss occurs
in approximately 15% to 20% of clinically recognized pregnancies in reproductiveaged women, RPL occurs in 2% to 5% of the same population.1 Recent reports on
large populations of women with RPL have helped to characterize the incidence and
diversity of this heterogeneous disorder, and a definite cause of pregnancy loss can
be established on over 50% of all couples after a thorough evaluation.2 New diagnostic
strategies, which include 23-chromosome microarray genetic testing of the products
of conception in failed pregnancies, offer the promise of understanding the cause of
most pregnancy losses.3 These recent advances, combined with the contributions
from the authors in this issue of the Obstetrics and Gynecology Clinics of North
America and many others interested in this field, led to the release of the long-awaited
publication on evaluation and treatment of RPL from the Practice Committee of the
American Society for Reproductive Medicine.4 A complete evaluation will include
investigations into genetic, anatomic, immunologic, endocrinologic, and iatrogenic
factors. The occurrence of RPL may induce significant emotional distress and clinicians must be diligent in making intensive supportive care available in some cases.
With a directed approach to diagnosis and careful treatment, a successful outcome
will occur in more than two-thirds of all couples.5
Miscarriages are considered any loss before 20 weeks (North America) or 24 weeks
(Europe) of gestation. Embryonic losses are those that occur before 10 gestational
weeks, and fetal losses occur from 10 to 20 (or 24) gestational weeks. Later pregnancy
losses are considered stillbirths and will not be a topic covered in this issue. Prior pregnancy history is an important prognostic factor: primary RPL is diagnosed in those
couples who have never had a previous viable infant, whereas those couples with secondary RPL have previously delivered a pregnancy beyond 20 gestational weeks and
Obstet Gynecol Clin N Am 41 (2014) xi–xiii
http://dx.doi.org/10.1016/j.ogc.2013.10.009
0889-8545/14/$ – see front matter Ó 2014 Published by Elsevier Inc.
obgyn.theclinics.com
xii
Preface
then suffered subsequent losses. Tertiary RPL is used to identify those couples with
multiple miscarriages interspersed with normal pregnancies.
The contributors to this issue represent some of the world’s most dedicated clinicians and investigators. Most of them have spent their entire careers working with
couples affected by RPL. Ole Christiansen, an obstetrician gynecologist who manages
patients with miscarriage through the busy Fertility Clinic Rigshospitalet in Copenhagen, has contributed an article on methods and flaws of RPL research. Roy Farquharson, consultant gynecologist, serves on the National Institute for Health and Clinical
Excellence and sees patients at the Liverpool Women’s Hospital’s Miscarriage Clinic.
His group has contributed a chapter on mid trimester pregnancy loss. Mariëtte Goddijn, a reproductive gynecologist at Amsterdam Medical Center Recurrent Miscarriage
Program and coordinator of the ESHRE Special Interest Group for Early Pregnancy,
has contributed an article on establishing a recurrent miscarriage program. Lesley
Regan, Clinical Professor at the Imperial College in London has contributed a chapter
on dealing with couples that are diagnosed with unexplained recurrent miscarriage.
A number of investigators and collaborators with the Center for the Study of
Recurrent Pregnancy Loss in Memphis, TN have made valuable contributions to this
publication. Carolyn Jaslow, an active teacher and research professor of Reproductive Biology at Rhodes College, has made significant contributions in characterizing
the causes of RPL and has added a review on anatomic causes of RPL. Brett Davenport has taken his data and provided a contemporary review of thrombophilias and
their potential role in RPL. Raymond Ke, a true reproductive endocrinologist and
practitioner in our RPL Center in Memphis, has written a concise update on hormonal
factors and RPL. Paul Brezina, director of the reproductive genetics program at our
RPL Center in Memphis, has provided a review of genetic trends in our field that will
impact patient care in reproductive medicine. To summarize current research, we
have devoted a summary chapter to the latest strategies for the management of early
pregnancy loss.
Finally, many thanks to William Rayburn for the opportunity to guest edit this issue
on Recurrent Pregnancy Loss for Obstetrics and Gynecology Clinics of North America.
It has been a pleasure working with him and the staff at Elsevier to make this issue a
reality. On behalf of all the contributors to this issue, we hope that this update will be
informative for you and beneficial for the patients that you care for with RPL.
William H. Kutteh, MD, PhD, HCLD
Vanderbilt University School of Medicine
Recurrent Pregnancy Loss Center
Fertility Associates of Memphis
Memphis, TN, USA
E-mail address:
wkutteh@fertilitymemphis.com
REFERENCES
1. Stephenson MD, Kutteh WH. Evaluation and management of recurrent early
pregnancy loss. Clin Obstet Gynecol 2007;50:132–45.
2. Jaslow CR, Carney JL, Kutteh WH. Diagnostic factors identified in 1020 women
with two versus three or more recurrent pregnancy losses. Fertil Steril 2010;93:
1234–43.
Preface
3. Brezina PR, Kutteh WH. Recurrent early pregnancy loss. In: Flacone T, Hurd WW,
editors. Clinical reproductive medicine and surgery: a practical guide. 2nd edition. New York: Springer Science 1 Business Media; Chapter 13. p. 197–208.
4. The Practice Committee of the American Society for Reproductive Medicine.
Evaluation and treatment of recurrent pregnancy loss: a committee opinion. Fertil
Steril 2012;98:1103–11.
5. Lund M, Kamper-Jorgensen M, Nielsen HS, et al. Prognosis for live birth in
women with recurrent miscarriage: what is the best measure of success? Obstet
Gynecol 2012;119:37–43.
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